First off I want to say I've loved playing through omni/nomi multiple times; I just keep coming back to it. Love the work y'all have put into it, it's really something special.

I know everybody has an opinion on these things, but there's a few extra mods that I always add despite the current set being already fairly extensive and complete.

In order of how 'crucial' I consider them:

Carry On

Curseforge link: https://www.curseforge.com/minecraft/mc-mods/carry-on
Description: Allows players to 'carry' / pick up and move most entities and tile entities intact. The 'cost' is that players hands (including off-hand) must be empty, and while carrying an entity / TE, the player is encumbered (move very slowly) and defenseless (cannot equip any other items until the entity is placed down).
Reasoning: This gives players a way to move or rearrange their factory at very little cost. It works flawlessly for all GT machines and blocks, all storage drawers, vanilla TileEntities, and even some AE blocks (interfaces, at least). The real advantage is for GT machines, it preserves their contents, augments / side upgrades, and configuration. No more having to break blocks to refactor your factory layout, losing precious fluids from input tanks or tediously having to re-configure upgrades! The ability to move passive mobs (cows, chickens, pigs) is also a great boon to the (very) early game, for catching and moving mobs into pens, as an alternative to using leads. This also allows you to place and 'pre-orient' a sided block with limited re-orienting functionality (ex: CEFs, I/O busses & hatches, which require using a wrench on the particular side you want active, which may not be accessible) off to the side, and then move it into place to achieve orientations that you wouldn't otherwise be able to without having to break many surrounding blocks to expose or access the side you want it to face.
Note: Specific blocks can be whitelisted / blacklisted in the config. The only block I've so far found to have an exploitable glitch are the PackagedAuto blocks, which pick up fine, but there is an error on placing them down that can create dupes; so these blocks would probably need to be blacklisted.

Compact Machines

Curseforge link: https://www.curseforge.com/minecraft/mc-mods/compact-machines
Description: Build complicated machine contraptions and hide them within a single Compact Machine block.
Reasoning: The value of this mod is two-fold: Graphical performance on lower end clients, and factory modularity. In regards to performance, it allows players with lower-end computers to moderate how many TileEntities are visible at a time by distributing their factory across multiple Compact Machine blocks. Although most factory TEs aren't particularly demanding, the sheer size / volume of factories towards the end game can really drop frame-rates and make laptops run hot; which is something worth avoiding for players without dedicated servers who want to leave the game running in the background unattended for hours or days at a time to accumulate resources from automation. As for modularity, it allows factories to be built in composable 'chunks' (both literally and figuratively), significantly enhancing refactoring ability as the factory grows. Its almost inevitable that no matter how well a player designs an initial factory layout, it will eventually outgrow its designated space and force players to spend hours either moving layouts around, or dealing with the ugliness of trying to jam too much in too little space. This mod also works great and complements the many GregTech & Modular Machine multi-block structures, which can be very space consuming and a real pain to move around. I like to make whole 'rooms' dedicated to automated stuff, partitioned by machine tier, leaving on-demand crafting to in-world. They also make for great and natural partitions for creating AE sub-networks, somewhat mitigating the AE performance problems associated with the size of a late-game monolithic AE network. Some multi-block structures are still too large to fit into even the largest CM (GT Fusion Reactors, max-size Assembly Line, MM Oil Rig, etc.), but the vast majority do. EIO conduits are out-of-the-box compatible with CM tunnels, as are any blocks with standard Inventory or FluidTank interfaces.

ME Capability Adapter

Curseforge link: https://www.curseforge.com/minecraft/mc-mods/capability-adapter
Description: Small compatibility mod that makes AE networks compatible with Compact Machine tunnels using an 'Adapter' block. Compatible with AE2 Unofficial Extended Life.
Reasoning: This is an essential add-on specifically for AE2 and CompactMachines, since AE networks on their own aren't compatible with CompactMachine tunnels. This mod adds a single 'adapter' block, required to be on both sides of a CM tunnel, that allows AE networks to traverse through a CM tunnel without requiring an AE Quantum Bridge, which would otherwise be very costly and consume much of the CM's internal space.

Less crucial

Random Things

Curseforge link: https://www.curseforge.com/minecraft/mc-mods/random-things
Description: Collection of 'Random' things, as name suggests.
Reasoning: There are many blocks and items here that offer various player QoL enhancements that aren't overpowered and are reasonably balanced. Its best to just read about the mod on its site, but a few of the highlights, in order of impact:
Time in a bottle (item): A very simple, reasonably early game item, that 'stores time' in a bottle, and can be used on any TileEntity to increase its tick rate for 30-second bursts. This may sound overpowered, but it's balanced by the fact that its accumulation rate is fixed, must be in inventory to accumulate, and only one can be in a player's inventory at a time. It can boost up to 5 levels; level 1 costs 30 seconds of time and doubles the tick rate, while each subsequent level doubles both the previous levels' tick rate and time cost (but does not extend the total boost time). This is great for early where players are frequently blocked and waiting for low-tier GT machines to finish a workload, but it does not come for free - machines that consume power (both EIO and GT machines), while ticking at an accelerated rate, also consume power proportionally. Most GT machines will exceed the supply capacity of their CEF or other power source boosting beyond level 1-2 (unless the power source is also boosted, which adds to the total 'time' cost) depending on the particular recipe and overlock level. Boosted power sources will also consume fuel proportionally, so again, nothing is free. This is similar to GT's overlocking mechanic, without being overly powerful, given that the ability to boost dependent on how much 'time' the player has accumulated.
Item Collector: An arguably better alternative to the Vacuum Chest. In comparison, it's overall more performant given that it instantly 'teleports' items in range, rather than 'sucks' them in, forcing the game to calculate physics on the item-on-ground entities, and items don't get 'stuck' by obstacles in their path to the collector. The upgraded 'Advanced Collector' provides slightly larger range, and ability to filter items, similar to a vacuum chest.
Igniter: A simple block that can start a fire either continuously, or in response to a redstone signal. This otherwise useless provides a specific niche use in farming EIO Grains of Infinity, by placing them on or above bedrock and set to 'continuous' mode, where they instantly re-ignite a fire on the bedrock that has extinguished naturally (and possibly produced a Grains of Infinity). It avoids consuming flint & steel charges, and can be automated with an Item Collector to pickup Grains of infinity.
Fertilized Dirt: An upgraded alternative to vanilla farmland that slightly increases crop tick speed, and doesn't require water.
Spectre coils / injector: Provide a means of wireless energy transfer in the early-mid game after reasonable investment into farming ectoplasm. Unlike AA lasers EIO dimensional transceivers, the transfer is 'tax'-free; but the default buffer capacity of the Spectre Injector (1M RF) and transfer rate of even the highest tier coil (~20.5k RF) make them unsuitable beyond powering more than a few EV tier machines per coil.
Chunk Analyzer: An alternative to the Scanner for finding ores in the early game. Unlike the Scanner, its range is limited to the chunk the player is standing in, but it has the bonus of being able to specifically identify the block types (and their quantities) in the chunk. It's particularly useful in the very early game when looking for specific ores that the scanner can't distinguish between (without the block module, which requires at least 1 ore of the given type).
Floo: An alternative, early game system for player teleportation.
Peace candle: Prevents mob spawns in a 3 chunk radius, great for protecting hostile mob spawns inside an early game base.
Spectre Illuminator: Like the Feral Flare Lantern, it can light a huge area. Unlike the lantern, it is limited to the chunk it is placed in, but can light the entire vertical space of the chunk, from sky to bedrock. Great for early game mining expeditions.
Block breaker: Yet another block breaker, but compared to AA's, it has no inventory of its own, instead placing blocks into an inventory located behind it (or dropping them into the world if there is none). It's also much faster (reacts to blocks placed in-front within 1-2 ticks), and the default recipe is practical for very early game. Specifically, I find these much better for early snad-sugar cane farms -- they're less messy and performant since they'll break the cane the moment it grows and place the drop into an inventory behind it, greatly reducing the lag in comparison to pistons which throw items everywhere, slower, and aren't as efficient given they're driven by redstone.

Lastly, I also add Tinker's, which is arguably against some of the concepts of this modpack, but I think greatly improves the early game experience for a few reasons:

• The crafting station alone is almost worth adding this mod even, if you blacklist everything else. I cannot tell you how much it improves the tediousness of the early game, when vanilla crafting tables and worktables are your only options. Compared to a vanilla crafting table, it provides access to an adjacent inventory (chests or better yet, small storage crates work best), and the pattern area keeps its state even if you close the interface. Worktables still find their use in retaining very frequent or repetitive recipes (all those early game ones requiring GT hand tools), but really, crafting stations are so much better for everything else.
• Early game ore-doubling (I know the questbook tries to say it's not necessary -- but as a longtime player, I can't break the habit of needing to get more than just 1:1 out of my ores, and early game GT ore processing is just too damn frustratingly slow and tedious)
• As a balancing factor, it has limited compatibility - Only basic ores are (out-of-the-box) compatible with tinker's. Specifically, vanilla and ores with common OreDicts (e.g. copper, tin, etc.). Beyond early-game ore doubling, it also allows early game alloying, but its also limited to basic alloy types.
• Seared Furnace provides an early game version of the Multi-Smelter and arrays of the More Furnaces variants, but specifically only really provides an advantage when doing large-batch processing of entire stacks at a time.
• Drying Rack provides a great early game way to obtain the initial leather needed to crafter other early game staples like the Glider, as well as enhance basic food items, or turn an otherwise annoyingly-useless-but-abundant rotten flesh into a very low-grade food, for desperate or hungry noobs.
• The tools and weapons it produces can be useful, but are entirely optional. The weapons in particular are (or at least, can be) better than any other early game weapons available for players not playing on peaceful, and the mining tools can be useful in the early game (in comparison to mining hammers) for those looking to go spelunking for ores by the fact that modifiers can provide perks like slow automatic repair (economic), and slightly higher mining speed or range. I did notice however, that in my case at least, that the mining tools had a sporadic bug causing them to sometimes randomly fling drops all over the place, sometimes up to 30 or more blocks away, even with the 'direct' (teleport drops to inventory) modifier, occurring as much as ~25% of the time. Tinker's mining picks are also useless for breaking GT machines regardless of their mining level or speed, as GT doesn't recognize them and treats them indifferently when it comes to optimal mining tool.

Hope this was't too much, and that you'll consider some of my suggestions. I strongly recommend at least play testing with them to evaluate for yourselves. I think even if you customized the recipes to fit into the 'expert mode' spirit of the pack and gate access to them to specific points along the game, that they'd all still be worthwhile and great enhancements to the gameplay and player QoL. Thanks for reading!

Also what about Ding?
It just notifies player when the modpack finished loading with a xp orb sound, cuz sometimes it takes a few minutes and i'm not really a fan of checking if it's loaded or not yet.

I'm glad you enjoyed the pack and I appreciate the feedback and suggestions. I am familiar with all of the mods listed, so I can briefly explain why we do not have them.

Compact Machines & ME Capability Adapter are pretty safe to add if you really want them; you're far from the first person to suggest these mods over the years. These mods don't have any known major problems and I am unaware of any game balance implications under normal conditions. They are however not sufficiently compelling to warrant putting in the pack.

CarryOn is a useful mod but as you note it has certain bugs which can implicate game balance. I also know it to cause problems in multiplayer: Neeve and I used it during a 1.2.2 playthrough and we had to leave the dimension entirely while the other was using it to avoid issues.

RandomThings is a grab bag mod and the majority of things it adds have analogues that already exist elsewhere in the pack. It would have to be stripped down so much that most of it would just be load time bloat. Time in a Bottle in particular is a tick acceleration tool which is antithetical to the design philosophy of good packs. There was even a serious suggestion to disable that item in scripts in the event someone added RandomThings to the pack.

Tinkers' Construct was intentionally not part of Omnifactory, and we have no plans to include it in Nomi either.

As for the other suggested mod Ding, that sounds like a clientside mod you could add if you wanted it. This pack loads for me in about a minute, and on my old hardware (processor from 2008) it took five minutes, so I don't personally see the appeal.

I'm glad you enjoyed the pack and I appreciate the feedback and suggestions. I am familiar with all of the mods listed, so I can briefly explain why we do not have them.

Compact Machines & ME Capability Adapter are pretty safe to add if you really want them; you're far from the first person to suggest these mods over the years. These mods don't have any known major problems and I am unaware of any game balance implications under normal conditions. They are however not sufficiently compelling to warrant putting in the pack.

CarryOn is a useful mod but as you note it has certain bugs which can implicate game balance. I also know it to cause problems in multiplayer: Neeve and I used it during a 1.2.2 playthrough and we had to leave the dimension entirely while the other was using it to avoid issues.

RandomThings is a grab bag mod and the majority of things it adds have analogues that already exist elsewhere in the pack. It would have to be stripped down so much that most of it would just be load time bloat. Time in a Bottle in particular is a tick acceleration tool which is antithetical to the design philosophy of good packs. There was even a serious suggestion to disable that item in scripts in the event someone added RandomThings to the pack.

Tinkers' Construct was intentionally not part of Omnifactory, and we have no plans to include it in Nomi either.

As for the other suggested mod Ding, that sounds like a clientside mod you could add if you wanted it. This pack loads for me in about a minute, and on my old hardware (processor from 2008) it took five minutes, so I don't personally see the appeal.

Just noting that Nomi-CEu has a compat script for Compact Machines, as it doesn't really fit the theme of nomi, but is a mod that some want.

A similar thing could be done for base nomi.