I always fail to anticipate checking past selections before leveling up.
It would be nice if the evolve button didn't replace the character image, so I could still go see all my old ones and try picking a new option. Would be even better if the name of each path was shown at the fork-point.
I've gathered a number of QoL suggestions for the Adventure Mode over the years, and while they all have merit, I most likely won't implement any unless a significant backlog of other things gets cleared up.