There's another aspect here that hasn't been addressed. One thing that has plagued a lot of BR releases is the misuse/overuse of DNR to smooth out the picture. PATTON is so awful it is unwatchable, with faces looking about as realistic and waXY as that of the 'knight' in SHORE LEAVE. Some TOS feature BRs have this problem to a degree as well.
When you go to 4K, there's going to be even more of a push toward these scrubbed, overly clean images, since people are unfortunately going to be getting used to not having grain in their imagery (note I say grain, not noise.)