Came for the UI, stayed for the gameplay.
So after playing the mod for 35 (two hour) days, I'm ready to give you my limited feedback. Mind though that I was playing v2.2.04 (stable) and some issues might be outdated.
The main selling point is obviously the user interface, which is really stunning. I was expecting to see just another mod with a cool UI, but boy I was wrong. The gameplay changes kept pleasing me. Initially I was skeptical about the inventory 'weight' concept ("yeah, whatever"), but quickly felt it was the only true way to play. It is just better than vanilla in every way. Also I'm very glad 'learn by doing' came back without sacrificing the perk system and without adding 'spam crafting'. I was so missing the 'you gained a point in athletics' messages

I wonder is it possible to adjust the message to tell us the current skill value. "You gained a point in athletics (now 23)".
I'm glad to hear you intend to give some love to cooking and farming too. Food is extremely easy both here and in vanilla. Just don't give food any more buffs, with all the buffs/perks/skills/gear the player is already OP. Maybe make the opposite: if you don't eat meat regularly, your strength drops, if you don't eat fat your weather insulation suffers, if you don't eat sugar (honey) you get -1 intellect, if you don't drink alcohol from time to time you get depression (-10% experience gain), something like that. That would encourage the player to diversify his food. Some use for snowberry maybe. I don't know your plans for farming, but increasing growth cycle would be the obvious first step.
I think you need some F.A.Q. either here on the first page, or better ingame (journal entries?). The new players ask all the same questions. Maybe make a quest line about research (the hardest question to figure out).
I like the research system (reverse engineering). The problem is, it is much easier to loot or buy the needed item than to research and craft it. It is not exactly your mod's problem, the vanilla game has taken the direction from crafting to looting for quite some time now. Maybe it isn't necessarily bad, just I feel all those new researching and crafting mechanics you have added are kinda underutilized.
All these new vehicles are nice, just not my cup of tea, I'm still driving my motorcycle. But I still haven't found the gas schematics. Day 35, constantly checking all five traders, looting-looting-looting, completed 16 of 19 book series and no gas schematics. You said the gas recipe is rare, but come on! Maybe just bad luck.
I'm also saddened that this mod is not supposed to be played without traders (or so it seems). You said that some vehicles are 'buy only', and I suspect some other gear too. Is it true? I dislike the trader gameplay and usually generate no trader map with nitrogen. This time I played in Navezgane with traders, but I'd love an opportunity to play this mod without traders.
Further are some minor questions/bugs/suggestions:
- I found out that gun turrets accept any ammo, does it affect its damage (like .38 HP vs 7.92mm AP)?
- Can we have a different icon for dart trap ammo?
- Also can we have the encumbrance bar of a more different color than stamina bar? I have trouble telling them apart.
- Maybe a center line on the compass?
- I'm looting much more "light armor parts" than "steel armor parts". Currently in my storage 174 light parts vs 10 steel parts.
- Bulk crafting ammo, is it removed? The books still mention it.
- Can't report 'nail some chicks' quest to a trader.
- I have the impression TFP made it so when comparing weapons/gear, mods don't affect numbers, but in your game I have to remove all the mods to compare two items.
- Also is it possible to show the vehicle info when I'm about to buy or to craft one? Currently I just spawn it with creative menu to check the speed/cargo.
- Carpenter axe (S tier) has only 3 slots and no dye slot. Also maybe repair it with a repair kit? I keep forgetting to take the two iron plating with me when going chopping trees.
- Make snakes venomous, add anti-venom?
- Make wetness matter again?
- I found a 'small backpack', that is a really cool concept, but it was the only backpack I found, I can see there are many more in creative menu, are they so super rare? Much too rare it seems.
- I found 'organic waste' with no use, is it a place holder for future farming improvement?
I hope my feedback was helpful, all above is IMHO obviously, you make the mod how you see it, definitely you know what you are doing.