“[The] Wii U has a horrible, slow CPU.”- Chief technical officer, Oles Shishkovtsov
“We had an early look at it, we thought we could probably do it, but in terms of the impact we would make on the overall quality of the game – potentially to its detriment – we just figured it wasn’t worth pursuing at this time. It’s something we might return to. I really couldn’t make any promises, though. We had an initial look at the Wii U, but given the size of the team and compared to where we were last time, just developing for the Playstation 3 is a significant addition.” - 4A Games' Huw Beynon

Is this a developer problem or a Wii U problem? We've seen other third party games crop up on Wii U without much issue. I guess we'll hear more on this as devs continue to learn/adjust to Wii U.