I’m kinda split on it, of course it would be disappointing to not be able to use the armor you’ve farmed for transmog, but at the same time unique body shapes make a lot of armor look bad, like good luck finding good plate helms and shoulders for male undead that don’t have severe clipping and weird angles.
If it is mainly barbershop customization, I’ll be fine if there’s enough variety and pieces that can be unlocked as gameplay rewards for the benefit of the custom fitting.