OK i think this is by far best overhaul mod for TW3 (currently):
W3EE
https://www.nexusmods.com/witcher3/mods/2521/
It is old overhaul mod but recently it was updated to 3.0 version (and then to 3.06) and it is huge difference from initial overhaul mod.
1. redos completely economy, alchemy.
2. combat is also redone (everything cost stamina even normal swing like in DS games and combat is much more deliberate instead of mashing things).
3. leveling is completely redone (you no longer earn XP via quests but increase skills by using them like in morrowind)
4. armors/weapons completely redone and most of weapons in game have more or less similar damage but you can create various builds.
5. added new weapons to use and non sword weapons now have use.
6. World in unscalled, meaning there are no levels and much like gothic what you see is how something is hard.
7. mutagens now have completely different use like green giving you more toxicity cap.
Imo the biggest change comes to weakest part of TW3, combat. vanilla Tw3 combat is basically hack and slash with 0 thinking.
In W3EE everything is deliberate and you don't swing like idiot because you will run out very quickly out of stamina and won't be able to even swing sword, much less dodge attacks.