LOD and such had mods too for anything from objects to characters though objects likely impact load times and performance though characters being full detail even outside of cutscenes would probably not hurt too badly although it likely mostly affects the more quest important characters. For 2015 it holds up well although 2013 - 2014 is where games started to fully push for a physically based rendering pipeline and that has really helped plus the feel of the game world in Witcher 3 overall and way it's designed though the HD texture and asset mod after some updates has also made a nice difference with some of the nice but lower-detail object in the game.
