I don't think it's being hard on AJ to criticise or not like Claudia and AJ's dances. Other than their Charleston, which I loved, I struggle to remember what they danced when I'm reminded they're in the show, i.e. next up is Claudia and AJ. Oh yeah, them. Or a final look at the leaderboard and their names are there, though it's getting easier the fewer couples that are left.
I remember a row of brightly coloured lockers as part of their set and I think it was a Foxtrot. As I'm writing I can't remember what they danced on Halloween Week. I do remember they danced the Samba, but for the wrong reasons in that there was too much content for her and it was too fast for her (actually agreeing with some of the judges for once).
I don't think it's his youth or his experience, I think it could be them being pegged as the "youth" of the competition and them living up to it.