In terms of exclusive support from 3rd parties... this game 100% will decide how things go post-release
The Wii U will receive healthy 3rd party port support regardless even after XBox Next and PS4 get released.
Will Nintendo themselves make another Eternal Darkness or such M rated quality game as a 1st party or 2nd party game? Nothing seems to be in the pipeline but time will tell. It seems unlikely though.







