The only open world game we had from mario was basically super mario sunshine. We want a new open world game from mario, or even a sequal to Super Mario Sunshine. Producer, Yoshiaki Koizumi Said and I quote ..." if a very large number of players expressed the desire for a more open Mario, we would take that request very seriously." 

Here's the link to the full Article/Quote : http://www.dualshockers.com/2013/11/03/open-world-super-mario-possible-if-fans-ask-for-it-3d-world-wont-have-dlc-gamepad-used-extensively/

So if Enough people support this we may get a new super mario open world game. Let's do this!