Board Thread:Speculation, Theories, and Rumors/@comment-26244866-20160131005308/@comment-2118191-20160303100532

Justbenn wrote: It seems that we have an uneven amount of character types on each side, hopefully the Wii U version clears things up. (Also Rosalina is tougher than Zazz, I did not expect that, I thought that Zazz would be Power type and Rosalina would be Skill type.)

To be fair, ever since she started being playable in Mario games, Rosalina has been fairly consistently portrayed as a "power" type character.