Miyamoto has wished to implement multiplayer in Mario 64. Would it be a great possibility for him with Galaxy 2?

Doubt it. They made NSMBWii to satisfy the cooperative/semi-competitive multiplayer thing. That's NSMBWii's thing. Galaxy 2 is not going to be about that.

Possibility yes. Great possibility? No.

Can't see it, one person would end up on the other side of a world, out of view, or you'd have to make the world's translucent but it'd still be hard to play. A multiplayer 3d Mario would need to be built from scratch I think.

I'd like to see some kind of multiplayer mode like they had in Mario 64 DS (with splitscreen).

Not coop, though, wouldn't work.

I hope to include a better multiplayer mode that first galaxy

if there is one itll be like the first galaxy

thats a great idea, why not?
would be alotta fun.

I don't think they've had the time to implement a good one yet, honestly. I don't think we'll see it in Galaxy 2, but probably in some future 3D Mario-title.

not for Galaxy, the game just insit built for multiplayer, maybe some mini-gamesl ike in Super Mario 64 DS

It's possible, but would be hard to accomplish. They will most likely make the system better from SMG.