And mechanically speaking, I think having so many classes means you often have to portion out certain abilities in odd ways that again has a huge impact on flavour. Like, Eldritch Knights should have an equivalent of Divine Smite.

Cos who's choosing to play a magical knight and not hoping to be able to summon arcane energy to their weapon and do a cool hit? But they apportion out abilities so as to have some crossover but not too many redundancies.