what about the return of the armored cannon beetle? It just disappeared in Pikmin 2. My idea would be a type of high-flying enemy and a new type of pikmin could fly to reach it. I have no idea what either would look like but it sounds cool.
you guys should really check out my topic! pink pikmin can fly! (it is mentioned in my topic) Also I have a couple boss ideas: Winged Bulborb, Evil Mastermind, Giant enemys (enemys the evil mastermind zapped with a growth ray!)