Touch controls when undocked, pointer controls when docked

Pointer.
With that, lots of touch screen games can be played while docked.
Even a game touch dependent like zelda phantom hourglass could be played just pointing to the screen. In this case, not having a second screen for the second view would be a worst issue. But not in SMM

You know a better question would be how will Splatoon work without the second screen, namely super jumping and inkstriking. Shoulda made that thread instead. :L

It could come with a cheap USB accessorie that plugs into the dock that lets the video signal be mirrored to the TV if you're using it from the couch and want to use the touch screen. Like a stripped down Google Chromecast kit, just with the video mirroring and nothing else.

From memory you could only jump to one of your team mates? Having the map pop up and just using the analog stick to select which one. 

Why would you need "a cheap USB accessorie" ? (its hopefully a part of Switch)

And I also thinks Switch can do this.. specally with less demanding games like Mario Maker

There would have to be some kind of receiver build into the dock to do this, which I guess Nintendo could do, but I think they want the dock to be as dirt cheap as possible. 

I am not sure at all we will have future Mario Maker games.

It looks like it's no.1 this week in Japan and has now sold well on both 3DS and Wii U. 

Nintendo doesn't one off ideas that actually sell this well (and no, Metroid generally does not put up these kinds of sales before someone brings that up). 

Anything from Nintendo that sells 2-3+ million worldwide is pretty much gaurunteed to get more iterations. 

Nintendo's system is fairly simply 

Sub-1 million sales worldwide - No sequel, unless the cost of the game is so low that Nintendo is willing to fund another one (read: low odds)

Over 1 million sales worldwide - Fairly decent chance of a sequel.

1.5-2 million sales woldwide - A very high chance of a sequel

Over 2 million sales worldwide - Sequel gaurunteed. 

Mitigating factors would be if the game had inflated sales due to things like heavy bundling. 

I think they wants it to be cheap to.. But this "a cheap USB accessorie" Makes sense is there from start.. imo..

It will make a lot of things.. (not only game related) posible.. and I also thinks it will go the other way (use stuff on dock HD when home)