It's a video game. Creating more animation, more clothing for the characters, is probably up there in the list of relatively costly things to add.
I wouldn't exactly complain if they increase video-realism. Characters could also get their armours bloody after fights, if they were in the front line spilling the blood of the enemies (or losing some of their own). They get their boots and trousers muddy if they walked through mud. If we ever get to go to a fancy event in Baldur's Gate, e.g. we're going to a VIP evening in the ducal palace, to meet and talk with some Duke, it would be great to go shopping for nice clothe before.
But ... I'd much rather they improve the gaming parts before they improve the video parts.