Feel like the games most needed by the Wii U:
1) a 3rd person 3D mario game, like Mario 64. However dont just do a lazy port, make a new real game.
2) a "real" paper mario game for the wii U. This means old school RPG.
3) a Pokemon rpg for the Wii U, ports would be acceptable.
I dont think Nintendo should try to do what the others are doing, with their much much weaker consol.
A new GTA game would be a huge letdown when you notice its graphics will be really lacking compaired to whatever the Ps4/xbone has.
It should stick to what its good at, that it has under delivered on.