Anime wise, I think we needed an episode where Goku taught him the Spirit Bomb, but Trunks couldn't manage it.
It might have been best if Goku learned the mafuba when Trunks was with him.
I think we should have had an episode mentioning hybrid saiyan potential, maybe Beerus saying the hybrid's could be unpredictable, or other types of hints towards a hybrid way of using God Ki. Maybe a hint with Gohan, to explain Trunks. I still don't think beating it over the head with the rage power up is a good thing to do, I think it should be random like that, but there should have been some type of hint towards it.
Shame about the Zenkai boosts, or whatever Black was getting. IMO that was one of the best things about Black.