they wont because my fellow Ninty fans will call them copycats... Or... Would they...?

Hmm this would be funny to watch how it plays out..

also would this game be under the "Play, Create, Share" genre also if it were to happen..

Nah, this would fall under the "Nintendo doesn't innovate" section:

Post this idea to Japanese communities in Miiverse - If Earthbound is any indication, Miiverse is the place to get Nintendo of Japan to hear you

 i suddenly have the urge to play this game :)

As long as the game is not only about creating levels...

Hmm not bad

That track editor really doesnt let you create anything. It just lets you add a couple things to an already created track. But now that i think about it, the op never said "creater" in the title so i guess it  wouldnt be worthy to gain that status.

I had to go back and check that out since ive never really played it. Also, what other level editors and track editors did Ninty make back then??

Smash Bros Brawl

Nintendo fans let me ask you this...

What would you prefer on the next Mario 3D Game, 10 new levels made by Nintendo or a simplified port of the level editor the used to create the game?

P.S.: There is no miracle in software development, everything is a trade-off. With the time spent creating a level editor Nintendo could create new content (is this case levels) for the game.

Hopefully Nintendo learned by now that user-generated content is a dead end.

This game had the perfect level creator, giving you equal powers to the game designers:

Pre-installed level:

User-created level: