I do not think she wil be in Kart for a few reasons. A)Super Mario Galaxy was released mid-to late last year. Mario Kart Wii was announced on July 13th. The game must of been mapped out before then with character inclusions, therefore either Rosalina is favourite at Nintendo or they took one heck of a gamble we would like her.

2) Nintendo is old school,heck they put in 3 characters in brawl who we havn't seen in almost 5 years. Going with a newbie is not like Nintendo. Would they sacrafice a vetran for a newbie?

3) Keeping Rosalina around is risky. Sure most people like her, but considering Mario has Peach-and they won't get rid of her- and Luigi has Daisy-who they could-shouldn't dump-there is no true spot for her unless she settles for Wario :p

My Roster
Mario-Middle Weight
Luigi-Middle Weight
Peach-Middle Weight
Yoshi-Middle Weight
Bowser-Heavy Weight
DK-Heavy Weight
Waluigi-Heavy Weight
Wario-Heavy Weight
Koopa-Light Weight
Baby Mario-Light Weight
Baby Peach-Light Weght
Toad-Light Weight

Unlockables
Baby Luigi-Light Weight
Dasiy-Middle Weight
Birdo-Middle Weight
R.O.B-Heavy Weight
Diddy Kong-Light Weight
Toadette-Lightweight
Toadsworth-Lightweight
Shy Guy-Medium Weight
Dry Bones-Medium Weigt
Baby Bowser-Heavy Weight
Boo-Misc
Mii-Misc