The big question is if they go for a fixed camera or user controlled camera.
Galaxy 1+2 had a fixed camera, because the Wii lacked a second control stick. For 3D land/world it was easier to implement 4 player and one could also argue a fixed camera is easier for young/new players to get into.
With DK Bananza already being a free camera sand box exploration game and apparently solo player, I think the new 3D Mario will go in a different direction.
I think it will offer 4 player again, but this time could be a mix between galaxy and 3D world







