I think it would be a nice addition if we could somehow filter the dragons that still need training vs those that have learnt all the new abilities they can. It's a bit of a hassle to figure out which dragons I still need to train when the ordering of them also keeps changing.
It would also be nice if we could say, reset a dragon's training, so if we accidentally 'overwrote' a sea ability with a normal ability, it would be nice to have the ability to reset that dragon's traning so that it can be rectified. Even if it meant resetting all the abilities to their defaults, I think this would be helpful.

You can keep training the dragon until all 4 new moves are learned. Therefore, just train the correct move over the move that had been learned wrong. It will be time-consuming, but it is a solution.