Quoted from the link of NEOGAF:
Eurogamer: To use Vita as a PS3 controller, the feature has to be built into the game itself?
Shuhei Yoshida: Yeah. It has to be built into the game. We've been working on the technical side, on how to make it easy for developers to be able to do that. It's still under development, but we should be able to demonstrate that functionally later.
WiiU "inventive" controller is not so unique anymore RE LOL. I foresee some problems with the WiiU in the future XD.