First off, I love the new Planeswalker selection screen. Huge improvement to the previously laggy and slow version.
What I’m suggesting is to allow customizable reordering of your planeswalkers. Dragging and dropping my most used planeswalkers to the top of the list would be really useful. Even easier, you could list them in order of most used to least used, instead of alphabetically. That would probably be much easier than the former, but both would be really nice!