Chaosmancer
Legend
We were talking about spell casting, not classes right? I didn't read the OP so I may have jumped in wrong. From a casting standpoint, there's essentially no differentiation outside of prep and rituals, which aren't enough to make things feel any different. My own taste would be to have Divine casters actually feel different in the actual casting. Specifically, their god should matter, and it really doesn't. I completely get the design impetus there, I just don't like the same-y feel of it. The kind of spells, and specific spells, are indeed different, but I think that's a weak place to differentiate. Just a flavor thing for me, it doesn't prevent me playing and liking 5e at all.
Yeah, I just don't see how it is possible to pull off without making the game far more complex than it wants to be.