I reckon if they do launch a Mario game for it, it will be a GameCube game I.e sunshine, or another Mario 64

They surely need a game that will sell the console and is not a Wii-port, A new exclusive Mario would probably help

If they made a SMG for 3DS, it would likely be exclusive to the new model, which I think is kind of dumb. Way to support early adopters of the 3DS/XL, Ninty.

No, they'll have one within a year of the launch of their next-gen handheld.

Super Mario Sunshine 3D/HD for New 3DS & Wii U, August 2015-$39.99

Rumor is Super Mario Sunshine 3D

I could see it being a remake or port, but not an all-new game.

If there is another 3D Mario game for the 3DS, it will use some New 3DS features, but not be exclusive to it.

I would prefer if they would not "waste" ressources on that. Better make a good WiiU one or make one for the 3DS successor. Mario 3D Land is good enough and NSMB2 is an okayish companion for that. No need for a nother one.

if they want to have one they should just port Galaxy over or Sunshine.

I see that more the likely. Games will probably have fucntions that work on the N3ds. But they still work. Rather than blocking the whole game to the revised handheld. ALA all black GBC carts. The GBA exculsive rooms on Zelda Ages/Seasons.