I kinda was hoping that Kirby would be in there T_T It would have been soo cool playing as him in MK8 like zomg

they are lame, this is coming from a guy who's favorite 2D Mario is Super Mario World :P

They could also add the fairies you free from the bottles in 3d world.

Hey the gameplay is still fresh and exciting. I do agree some more diverse characters are needed, but not get every Nintendo character.

There would actually be an endless list if they did this when we even include the diddy king racing crew. The thing is, that they can't pull out all the stops. This is not the final mario kart game and they need room for exansion for Mario Kart 9 +

The game is selling ridiculously well. To add any more would be overkill in all relevant logical sense. 

I don't think they should simply transplant the Smash Bros roster into Mario Kart. I suppose they could have a few guest characters or something, like Kirby. Mario Kart has its own history and traditions.

Like it or not, the babies aren't going anywhere. Kart (E) has a much broader demographic than Smash (T). I assume the babies are popular choices for younger players.

Common Mario enemies like Koopa Troopa and Shy Guy are series mainstays as well. You'd never see a regular Lakitu playable in Smash Bros.

I don't doubt that the Kart roster will continue to grow and expand, but for the most part, it will do so within the Mario universe.

I honestly don't understand why they didn't keep all the characters they had previously and just add more. Like, we can have the Koopalings AND Bowser Jr can't we? And why get rid of Dry Bones for Pink Gold Peach? There were certainly a few interesting decisions made in the character selection process for this game.

Wait for the DLC. I would really love Abe to be in there (Abe New N Tasty). That would be fantastic!!

no.
but i understand.
no one would complain if there was more 4 or 5 characters.

i played with some girls, they like to be girl princess or babies.