I feel like the classes are mostly fine as they are for combat as long as the DM plays enemies resourceful enough to deal with all the dumb combos casters can pull off later on.
I do feel bad for the Barbarian though. He doesn't even get most of the excuses presented for martials, with no extra ASIs/feats and being long rest based on Rage, a feature that completely defines them and is pitifully easy to run out of mid-fight, and you can't use it as much on a longer day that'd favor a Fighter or a Monk. Being really MAD too, so spending feats on more utility ones can mess you up pretty badly, and his high-level damage scaling is basically the very tiny increase in Rage damage, and Brutal Critical which is just bad.