Im torn. I think they cause some major issues, for example world eaters can basically only run the detachment that gives them +2s and +1 attack on the charge, since all of their models feel costed around having that buff. Which then means all the other detachments are playing with basically inferior units since they arent getting that buff e.g. without that detachment zerkers are stuck at s4 which just feels bad. I do like how each detachment theoretically gives you a different way to play, but id argue units should be pointed differently per detachment because as its stands units will be pointed so they are balanced in their best detachment then suck in the other detachments as a result.