I've always found it kind of dumb that pokemon in canon can only know 4 moves at once. I think it should be made to be like a more complete RPG magic system where you gradually get access to every move the pokemon can learn and then pick a composition of certain moves to actually use in battle. PP is also dumb and should be replaced with stamina. Another interesting thing to mention is that the amount of moves pokemon could know in the anime was left ambiguous until 3rd or 4th gen, which was much better in my opinion.