If the PS4 just had backwards compatibility this would be a no brainer.
The two games I'm waiting for on PS3 are MGSV and Persona 5 but both have also been announced for PS4 so the new console would actually have at least two games this year and next year for me to jump into along with Type-0 and if SE ever decided to release the FFXV demo more openly.
On the other hand, Xenoblade Chronicles X is coming out this year as well for the Wii U...
I'll probably take my GF up on the offer to use her PS3 for the time being. So I may decide to save those pennies for a new console to pick up before the year is out. So PS4 or Wii U?