Pickaxe: pickaxes pierce, so i think for pickaxes for each tier should have x damage guaranteed regardless of armor
Shovel: shovels have a wide face, so when you hit it should "stun" and stall the movement for a very short time
I also think you should try to implement the increased reach attack from combat tests. I know you dont want this to be a combat test clone but i think this seems to be the most compelling part of the combat update imo
Other notes:
The other two issues right now can be resolved with this client mod, but maybe not what you want to enforce on server: https://github.com/florensie/no-weak-attack
Bow and crossbow looting. i have seen many mods for every other tool except this. I think i can probably help with this because it is a simple mixin
Edit: had another idea: remove invincibility frames because when i shoot multishot it bounces off the target if more than 1 arrows hit

Hello, thanks for the ideas! I will need to split those in different issues I guess, and I'm not sure to do all of them but that's cool you share them =)

• Shovel and pickaxe: this definitely needs me to think more about it. That could be a thing, I don't know, but this will need as usual to find the right balance if I add it. Give me time to think about it ;)
• Reach: it should already be the same thing than combat snapshots, but I acknoledge I didn't test that much the combat snapshot. I will check again if it feels different but values are accurate
• Weak attack: I'm not sure I understood this part of your message but see other issue
• Bow/Crossbow looting: why not. Bows are too OP so I don't know if it would be a nice thing but maybe with a different value than sword looting. Or only on crossbows to allow looting with range attack, just like looting is only available on sword and not (pick)axes.
• Invicibility: that's a combat snapshot feature but if I'm right it applies only to projectile because otherwise you would get instantly killed by mob hords. I may add it in the future but I didn't think enough about it.

In a more general way, combat snapshots features are mostly good. I added the most important ones to me and the ones I was sure was a good idea (in my opinion). Others can be added if I think more about, but more importantly if I have time to add them, because modding is not my work so I do it in my free time.