Yeah, he'd have to work up to godly-level in terms of powers but it would be a unique way to keep the abilities he already has. And I mean, who doesn't want to change into a dragon? It can start small like an arm changes or grows scales strong enough to stand up to a blade and then when he gets better/stronger, eventually he goes full dragon.

I mean he did make a toilet explode early into canon so it wouldn't be a terrible new quirk? But basically his mood is reflected in nearby water sources, you could even add in the good feelings.