Ancient Warfare is a great mod, very intelligent, complex yet intuitive, makes Minecraft MUCH more interesting to play. Here are some suggestions to make it even more interesting:

Iron staples
Main purpose: makes it possible to build walls that cannot be destroyed quickly (like obsidian – but they can be broken with normal tools, not only with diamond pickaxe), that is, to build efficient castles/fortresses.
Produced 8 per iron bar
Applied to stones of worked material (“baked” or polished, not to dirt, sand or raw stone) after they have been set/built (doesn’t matter on which side you apply them, always show on all sides)
Show lightly on the texture (very small, hardly visible), one on each side of the block, not in the middle of the side, but where stone bricks join.
Can also be applied to iron gratings, doors and trap doors (but not to other wood items). Then these are more difficult to destroy, but still easier then stapled stone (in reality, gates always were the most vulnerable part of a castle)
Stone with staple takes much longer to remove (e.g., 1 min. per block with iron pickaxe, 30 sec. with diamond pickaxe) – for everybody, including the player who set the staples, so be careful!
When stapled stone is being removed, it gives a clear, metallic sound (which spoils surprise attacks)
No other blocks can be fixed on the sides or under stapled stones (but blocks can be put above them) – Purpose: It is not realistic that you can just fix some blocks on an existing wall to form a stair and then storm the castle.
Staples take one day to be effective (say, “the cement has to cure” – staple texture changes in colour) – Purpose: this is to avoid easy immediate repair during siege

Alternative: Battle Slowdown
It takes much longer to set/remove blocks when enemies are around. E.g., it is not realistic that you just quickly construct a wall to protect yourself against an overwhelming number of enemies when inside an enemy castle.
Like: you cannot sleep in bed when monsters are around.
Maybe it would be best to combine Iron staples and Battle Slowdown

Bar on door
Made of wood
If applied to one side of a door/trap door, makes it impossible to open that door without removing the bar.
The bar can be taken away only from the side of the door on which it was placed, making it impossible to open the door from the other side.
Own soldiers and own villagers “respect” the bar and do not open the door at all. However, the player and other persons (other players, brigands, barons etc., see below) may take the bar away and open the door (one right-click only).
Of course, the door can still be destroyed from the other side. To make this more difficult, staples should be placed on it.

"Independent Ladder"
Main purpose: to climb castle walls
Can be set like independently, without a wall, on any solid block
Will always go straight upwards
Several pieces can be built all at once (press shift) up to 20 blocks high – so you get, e.g., an 8-block-high-ladder in an instant
You can only get off the ladder where it touches a solid block
When on the ladder, speed is diminished as under water (to increase chances of defendants)
When one piece of the ladder is destroyed (even if it is the top one), the whole ladder falls (you cannot pull it up)
It can be destroyed by defendants on the top of the wall with few strokes of a sword or one push of a spear
Players/Creatures on falling ladders get harm from falling

Horses in battle
Purpose: make fighting on horseback easier and more realistic
If you take any weapon or tool in hand while on horseback, the head of the horse shifts from the centre to the left. The practical purpose of this is to give a free view on your enemies – as it is, the head of the horse is in the way and makes it difficult to aim at enemies. The intuitive explanation is that you don’t strike over the horse’s head if you fight on horseback. You strike on the right side of the horse’s body (if you are right handed).
If you ride, your left hand is empty to hold the reins. Your shield, e.g., is still kept in the left-hand slot, but it doesn’t appear any more and it isn’t effective any more. The practical purpose of this is to make it a little easier to fight enemies on horseback, especially with arrows. If riders move, it is very difficult to shoot them, but once they stop, e.g. because there is a phalanx of halberds in their way (see next paragraph), they are an easy aim for archers.

Spear
Purpose: make horses more interesting in battle; make defense more effective
If riding on horse: works like a horse lance, 3m long; very powerful if you hit an enemy with high speed
If on foot: works like a halberd, 4m long; very powerful against horses, does not let them come near enough to strike; speed of knight on horse/running enemy will add to his own damage
However, cannot attack very close (there must be 3 blocks in between); consequently: good to fight in a group, keeping enemies at distance at all sides, bad alone, since you cannot attack when enemy comes too close. He may get around you and attack you from the side. Works very well in combination with archers.
Also good to defend narrow passages, like breaches made by trebuchets etc. or destroyed doors
Also good to destroy independent ladders
If enemy does not ride/run into the halberd, harm done is smaller than sword, but bigger than arrow

Trebuchet
Costs lots of materials or: can only be bought from weapon smith at high price or: can only be conquered from barons (see below)
Works slowly (once every 30sec.)
Must be loaded (like bows need arrows); eventually: effect depends on load: iron much more effective than cobblestone, e.g.)
Works like this: player “enters” Trebuchet, with right click, like mounting horse. Then he takes a stone or other block in hand. Throwing it with the trebuchet now works like shooting an arrow from a bow (but takes much longer to “load”). The block will be shot off in the direction of the players vision, then follow a parabolic trajectory, like arrow.
Destroys on average one stapled block when hit and removes the staples randomly on half of the adjacent blocks.
Destroys on average 3x3x2 non-stapled blocks plus some random adjacent blocks
Harms creatures a lot when hit directly (not very probable)
Throws load high - over walls, hills, e.g.
Reaches far, but accuracy decreases with distance
Not so easy to destroy

Catapult
Main purpose: defensive weapon, destroy constructions by the besieging party, like bridges, ramps, earth ramparts etc.
Destroys easily any material without staples 2x2x1 plus some random adjacent blocks
Works like trebuchet, but much quicker
Once you entered it, it will “go with you” (different form trebuchet), i.e. you can “push” it to another place
May destroy TNT before it explodes
Harms creatures within a larger area (4x4)
Medium cost
Medium range
Easily destroyed
You can allocate a soldier to a catapult; then he will shoot enemies in range.

Ram
Very efficient in destroying stapled blocks, one at a time
You enter it like a trebuchet or ram, but different from them it will give you protection. Then you take it to a wall (will “go with you” once you entered it; will move slowly, like under water, you cannot run with it) and destroy blocks with right click
Needs direct contact with the wall
Difficult to destroy

Fight in formation
Would be useful especially for halberd and archers (form a line, a U or a rectangle)

Brigands
go around alone or in bands up to 4
Are very fast – run like player
have a hut where they keep their loot and where they go back from time to time, usually in a wood or swamp
Chests in brigand’s huts (and robber baron’s castles) start out with some few items (huts: without much value, brigands are poor; castles: medium value/quality, but high quantity). Then get more items as brigands/barons are successful in robbing.
not very heavily armed (except if they robbed armour/weapons), leather armour, if at all, no horses
fight to rob personal inventory, i.e., you can surrender, and they will take what you are carrying
will not besiege nor search for chests, but will empty chests if they see them, look through windows (will rob chests in villages if they see them). Will open doors, search passages etc.
rob fields, slaughter animals for food (they are a poor lot)
if you fight them to death and win, there is a 50% chance that they surrender and offer to become your soldier
Brigands and barons (see below) are “people”; monsters will attack them

Robber Barons (or: robbing pirates, wikings etc.)
Heavily armed, mounted when outside castle
Always in groups/small armies
Have well-fortified castles with precious loot, usually in high mountains or on islands, about every 2000m.
As long as they do not go on a campaign, they travel around in small groups, looking for people to rob. May rob player like brigands do when he is walking around. Also rob brigands.
Are fast on horses (evidently), but slower than brigands/player when on foot
Will start an army campaign against the player if he has accumulated some riches (diamonds, gold, etc.), i.e., will try to get to the place where these riches were exchanged (see next paragraph), will besiege if necessary. If there are several places, they will go first to the one which promises most riches, i.e., where most valuable items disappeared from the players inventory. Since they also rob brigands, you can give valuables to a brigand so that the barons rob him first, not you.
Different groups of barons will not attack one another
Information system: baron will "sense" inventory changes of valuable items (gold, diamonds, lapis lazuli, sapphires etc., products from these materials) at large distances (e.g. 1000m; say: “people talk about it and sooner or later message reaches the barons”); this distance increases with the value of items (e.g.: a full diamond armour will be “known” 5000m around); barons “count changes”: if, e.g., different single diamonds are put in chests several times in a certain spot/area, barons will sum them up; technically, once a certain quantity of riches has been accumulated, the program looks for the chunks in the respective distance where baron castles could be generated a generates them; once barons sensed riches, they will try to get to the place of the change to rob the items (on the assumption that the items should now be in a chest or on the player, who should be nearby; if they do not find the player on the spot, they will search for them around the place for a while). Once items are stowed away, barons cannot sense them anymore. (That is, barons do not sense untouched treasures in temples etc. – only when the player takes them out. However, if they accidentally get on top of a hidden treasure, it will come up to them, see next paragraph. They don't "see" the player moving around with treasures, they only know the locations where he put them into his inventory) Barons do not sense exchange of raw material (e.g. gold ore, stones with diamonds mined with silk touch).
They have the magic power to extract riches from chests under them and besides them (do not need to dig) but must be directly (or in an 4 x 4 area) on top of them or at their side. This is to simplify programming – so that barons will not have to dig underground. This also is to make castle building necessary. It is not sufficient to just bury your treasures very deep, you must block access to the surface coordinates of your treasures. Robber barons will try to get to the exact spot where valuable items disappeared from inventory and walk around a little, if necessary. They cannot extract items from personal inventory. They can only take from personal inventory if player surrenders.
Will ride over water, like with “frost walker”, but on horse
Besides their “natural” magic powers, they do not actively use magic. Will not rob magic books, apples etc. However, if they rob an enchanted armour or weapon, they will use it
They will remove obstacles on their way (by hand or with trebuchets, rams etc.); however, if possible, they will get around them (they look for the easiest path to their goal)
Size and equipment of baron’s army on campaign will depend on amount of riches (a lot of diamonds means a strong army with trebuchets etc.)
Will use trebuchets, catapults, ladders etc. to get to player/chests (i.e., to the place of inventory exchange and to the player, once they see him). Will construct bailey bridges (always made of wood) and ramparts, fill moats (with earth) etc. They have an infinite supply of building materials for that (but limited number of trebuchets etc.)
If the player’s castle is on an island and they cannot get a foot on the island (walls all around), barons will try to construct a bridge of wood from the nearest beach to get ladders, trebuchets etc. to the castle (these “swimming bridges” can get very long)
Baron’s offensive weapons also work as pickaxes, shovels and axes, with the same efficiency on stone, dirt and wood as those (this is to simplify programming: they do not have to change weapons/tools as they besiege the players castle).
Barons will plan their siege if they find the place fortified (e.g., if attacked and they cannot get easily to the attackers, they will use ladders; if this doesn’t work they will retreat and try to break walls/obstacles first)
Will destroy fields and animals close to the player, to starve him
Will fight player like brigands do; will fight every person/creature which attacks them. Player may surrender - then they take his riches
Golems do not attack barons (if not attacked by them – which barons do not do)
If you fight a baron to death and win, there is a 25% chance that he capitulates and offers to become your soldier, with armour, weapon, horse etc.
If a campaign is not successful for some time (several days), barons will go home (they run out of supplies); but will come back after some time
After a successful campaign, barons will go back to their castle and celebrate; they will not come out again for some time (say two hours)
Every time barons get back to their castle, their supplies (weapons, armour, trebuchets, food etc.) are restored.
Half of their casualties also are restored: if 2 barons die, one day later (not immediately!) one spawns at the castle if there are barons (garrison) in the castle. There, the new baron will wait until the next campaign, i.e., he will not reinforce the ongoing campaign. That is: if you “clean” a baron castle, no more barons will spawn. (But barons may come back after campaign and “repopulate” castle.)
Eventually: one new baron spawns for a certain number of valuable items robbed by the barons, so they get stronger by robbing.
Attack by barons is almost sure once you accumulate gold, diamonds etc., but it usually takes some time for them to get to you from their castle – they must plan their campaigns first and they do not move quickly if they are not attacking.
If a large party of barons (say more than 10) is approaching, the player receives a warning (say: “such a large party cannot travel unnoticed; notice spreads to the player”). The warning may be a sound of faraway weapons or of a trumpet.
When being attacked by barons while traveling, you can try to ride away (if you have got a fast horse), run into a dense forest where horses are slow (barons do not like to get off their horses), climb very steep mountains or dig yourself a hideout (if they still are sufficiently far away). After unsuccessfully looking for you for some time, barons will go away.
Player may dig his way into a robber baron castle, but it always has three layers of stapled stones as a foundation, and barons will hear the player braking stone underneath, which will spoil the surprise. (Possible solution: TNT – but you will need a lot of it to break stapled stone)
However, it is possible to (counter-)attack the castle while the barons are away on campaign (the only leave a small garrison), trying to attack the player or some brigands, e.g.
Of course, if they come back and find you in their castle, they will fight you – if you “take the castle” and there still are any barons left outside the castle, they will always try to reconquer the castle – technically: try to get back into it
If they are not successful in reconquering their castles (i.e. if they run out of supplies before they can get into it again), barons become homeless knights (see below) and go to some Inn.
Barons will fight to death (not only rob) any non-baron within their castle
Eventually: Every robber baron castle has a nearby village attached to it which supplies the barons as their feudal lords. When you clean the castle of barons (“take possession of it”), you automatically become lord of that village (see next item)

Village Lord
If you kill a certain number of monsters, brigands or barons on the village territory and/or build an iron golem for them (and/or take the castle to which it is attaches, see above), villagers will elect you as their lord. They will pay tribute to you, each villager according to his profession (scientist will give researched recipes).
If you increase the villages inhabitants and productivity (build fields, stoves, bookshelves, beds for the villagers to rest, etc.), you evidently will get more tributes.
You can take tributes manually directly from the villagers. They have a slot where they place their tribute.
To receive tributes, you can also build a warehouse within the village where the tributes will automatically be stored by the villagers
Technically, the program will just take the items out of the villager’s tribute slot and fill them into the warehouse. Evidently, other players or brigands may rob the warehouse. To prevent this, you must protect it.
Villagers will continue to sell items to you

Country Inns
Stand alone in the country, illuminated, usually well visible (like villages)
Here you may find unemployed, homeless villagers, brigands and knights who are ready to enter your services for payment (sapphires).
The landlord of the Inn is a fence. He sells items the brigands and barons robbed and do not want to use themselves (they will use food, weapons and armour for themselves). You may eventually be offered items which had been stolen from you
He also may sell you information about brigand’s huts and baron’s castles (sell maps)

And finally: Thank you for the great work you are doing!