While Witcher 3 provides many ways of modding, there are things that mods cannot do and some limiting restrictions.
One File Per Mod[ | ]
Due to how the modding implementation in The Witcher 3 works, mods conflict with other mods if they modify any of the same files. This includes Scripts, XML definitions, textures, models, and pretty much everything else. While this might sound like a small deal, some of the files are absolutely giant and touch on many different things.
Example: The r4player.ws file contains script that defines how the player interacts with... everything. If you wanted to modify how targeting works, then you'd need to change this file, but if another mod was changing how the camera works, they'd also need to change this file.
Overcoming with Script Merger[ | ]
Script Merger merges mods into a single meta-mod so that many mods can modify the same file. It can merge more than scripts as well. Generally speaking, everytime that you install, update, or remove a mod, you should be running Script Merger again.
Things Mods Cannot Currently Add[ | ]
Note: This list might not be complete or accurate! It was compiled based on information available with Witcher 3 1.12.
- Landmasses
- Quests
- Sounds
- Proper dialog, though you can create some dialog