5 types of Pikmin per game is a decent amount. However, Even if they did increase this number of pikmin you can have on the feild, to me there would be way to many pikmin to manage and even if I could manage it you could potentially become very Over Powered with lets say 150-200 Reds or Purples. So in the end having only 5 types of Pikmin per game is the perfect amount. Sorry.