That doesn't mean I don't understand the vanilla feel where paladins aren't supposed to be on par with warriors, I like the idea of them being a mix, where they are capable tanks/melee fighters but their purpose is to support the group overall, yet warriors should still be top tanks, because of class fantasy.
Same thing with priests, sure they can be shadow and deal some damage, but they should not be competing with true damage casters, hence a reason to have something like dual spec available, best thing to ever happen honestly.
Basically keep the idea that classic tried to convey, some classes are inherently better at certain roles, don't try to homogenize them like nowadays, but don't butcher the idea of multi spec classes either, make them viable in certain scenarios rather than complete junk or simply a chore to play.