Mario Kart would be a mess if they included all the Nintendo characters. For starters Samus, Star Fox, Falco, and Captain Falcon would have an unfair advantage.

The day I see Zelda in a kart-race against Kirby I will gladly cut off my gaming thumbs and buy a Kinect.

Not trying to be mean or anything, but who wants to play games with strangers over the net? Makes no sense. -_-

DQ characters and Mario World Characters.

Mario Kart and Tennis are the holy grail of Mario Sport games, and I don't think they should be opened to all Nintendo characters. A special visitors circuit made of 4 tracks based on other games might be cool, though.

Big team sports, though? Soccer, (American) Football, and Baseball would be awesome if all the teams were different Nintendo franchises.

well seeing as my friends are not they type of gamer i am, i dont have anyone to play with, and then there's my fiance, she hates mario party, so with online i can meet people like me who like the same games.

Lack of irl friends with the same gaming interests, or at least not having such friends immediately accessible (the place i'm currently at plays a lot of Smash Bros and Mario Kart local multiplayer, so i luck out for now), is definitely a reason to opt for online play even in games that are better-enjoyed locally. So often do i end up having gaming tastes distinct from my friends.

Not trying to be mean or anything, but who wants to connect and talk with strangers over the net? Makes no sense. -_-

(actually, I kind of am trying to be mean)