Paladin makes some sense because they are the type that absolutely needs the mechanics to be fixed, proper reactions and such for smites and abilities.
And I do see new classes as more mechanics than new content at this stage. Like how Druid showcased transformation mechanics (which matters for a lot of spells), helped highlight even more issues with concentration, and showcased small bits of positive homebrew and small bits of negative homebrew, as well as showcasing that spell mechanics need more work.