Things that are really going to bother me is the complete lack of race customization. you probably can't change any physical features of the Lizardman, Mutant Malfested, Malefic, and others. Playing a Lizardman will get stale if they don't end up adding choice for different faces, tails, head shapes, etc.
Not to mention horrible symptoms from 5 still carrying over, including shoulder pads and belts floating around the hips of characters not wearing pants or a shirt, armor being removed from clashing with each other for lame reasons, and the tails on the horned and beast race being reused stiff accessories is really underwhelming.
Shame, too, because we probably won't even get all the armor from 3 and 4 that didn't make it in 5...