I've seen many who agree, Wightborn just kindof looks like weirdly translucent black pudding-people.
Personally, I would suggest straightup turning the population models into skeletal. The skulls for them already exist, all you'd need is the different legs and bam, undead look cook and undead, not pug-like! Also, the option to keep skin and facial hair on your leader at least might be cool, would love a beardy lich, but I understand models might look like theyre hovering in some cases without specific case adjustments.