For Morrowind it didn't just upgrade the rendering, it completely changed the aesthetic of the scene. Is that on purpose? At that point you can't call the results better, only different.
It seems like the big change is that the light sources now actually emit light so the scene becomes a lot brighter. Maybe part of the process should be turning down global illumination? That might make dark corners even more dark however, and "hidden" clues that were supposed to be difficult to see may become outright invisible.
It seems you'd certainly be able to go in and just tweak the lighting without doing all the AI touchups, texture upscaling, and model swaps as they did in the video. Pretty wild stuff, either way.