Rosalina WAS indeed in Super Mario Galaxy 2. If you completed the game 100%, all 120 stars (Which I DID and the final level WAS HEELLLLLLL!!!!!!!!!!!!!) Rosalina appears from the sky out of her observatroy and stays on Starship Mario.
I love it! I just love how you where able to bring out that texture. Best part of Rosalina is she is different from Peach/Daisy. I guess the reason why she will always pwn is b/c a) she isn't purely another clone like Daisy b) her dress and c) She is the star goddess lol