SKMBlake said:
Conina said:

Super Mario 64 can also be played on DS (port), 3DS (BC of the port), Wii (VC) and Wii U (VC).

Super Mario Sunshine can also be played on Wii (BC).

Super Mario Galaxy 1 + 2 can also be played on Wii U (BC) and Nvidia Shield console (port).

So why shouldn't it be possible or allowed to play 3D World and 3D Land on Switch? Because reasons?

You can't play Sunshine with the Wiimotes and you can't play Galaxy with the Gamepad because they're heavily linked to their original controllers (which are mostly designed based how you play the 3D Mario game of the console).

And btw Super Mario 64 DS is a remake of SM64 with more playable characters, not a port.

On the Wii you just connect a GameCube controller (first or third party), problem solved.

And since the controller layout of the GameCube is very similar to any other modern controller (Xbox controllers, DualShocks 1 - 4, Wii U tablet controller, Wii U Pro controller, Switch Pro controller, Switch Joycons...), I'm sure Nintendo would figure it out to make Super Mario Sunshine HD compatible to the different Switch controllers. If users of emulators can do it, Nintendo can do it, too. 

The Super Mario Galaxy games already officially support normal game controllers on the Nvidia Shield console... so there would also be no problem for Nintendo to port them on newer Nintendo systems like the Switch. Additional the JoyCons have motion controls, so a Switch version could offer both input methods.

The "heavily link" between 3D Mario games and their original hardware and controllers are much less important than you suggest.