*Increased Sci-fi theme with junkturrets (and now drones coming?) - Easy to remove
*Removal of gun and motorparts, affects final product - Cannot be modded back in. Gun parts can be modded back in and then you use those to make an item, but not affect the quality level. The "assembly" window is the new mods window.
*1-600 Quality levels. - HIGHLY unlikely. Looking through the DLL, 255-ish seems to be the max.
*Random Stats - Easy to remove
*Sleeper zombies removed the feel of a zombie infested world. - Why? I'm not 100% sure they were in A15 but they definitely were in A16. You should be able to remove them though by just removing all sleeper references in all POI XML files.
*Jumping zombies. looks ridicoulous - Can't be fixed cos they jump whenever there's something in the way, like a small rock (and yes, it annoys the crap out of me)
*No corpselooting - Super easy to put back.
*Smell removed - Would need a DMT mod to turn back on. The code is there, it just needs hooking up.
*Dungeonstyle POI's - Grab the A16 prefabs and convert them. It takes a while, but it can be done. Then you can just edit RWG to only spawn those. Done.
*Traders OP - You can remove the quest option from the trader dialogue so they only sell/buy stuff.
*Leveled things - A pain but do-able.
*Overall shift of being hunted to being a hunter. - Not really sure how you'd fix that other than to just jack up the zombie spawns.
*No Hubcity. - I don't think nitrogen has a "generate central wasteland and city" option. Which is a shame. Cos I miss it too.
*Learn by Doing. - Can be MOSTLY done. Some skills don't work at all (like barter)
*Magic learning skills - If i'm understanding correctly, you don't want to be able to use skill points to learn stuff. This is MOSTLY do-able, but then skill points would be pointless. But in theory, you can just remove perks, or make them have a cost of 0 so you have to find the books.