Super Mario Galaxy 2 director Koichi Hayashida has told Game Trailers that the team would have liked Donkey Kong and Pikmin to star in Super Mario Galaxy 2, but Shigeru Miyamoto wasn’t too keen on the idea.
“One of the early proposals that we discussed for Super Mario Galaxy 2 was the possibility of including characters from other [Nintendo] franchises. For example, you might have Donkey Kong or Pikmin show up.”
“We presented this to Mr. Miyamoto, but he came down pretty hard, saying that there has to be a functional reason to include characters of a certain type in a game. He went to specify precisely why the Pikmin wouldn’t work.
“In the Pikmin games, you’ll notice that all the Pikmin are very thin – tall and narrow for their frame. Mario enemies tend to be on the short and squat side and there’s a functional reason for that. They’re easier to stomp on. They’re lower so you can get above them and broader so you can land on them. In that sense, Pikmin are just not well suited for the Mario universe.”