They get not just GTA5, They'll get a second exclusive Lego GTA.

This is a no brainer Nintendo has pushed hard for GTA receiving one on GBA and DS. Now that WiiU is more powerful then the competitors and with DLC now coming and Nintendo Network. Plus the rumors and past comments of how much Rockstar wanted to work with Nintendo sooner or later. I am guessing Reggie himself has been pushing Rockstar and probably has visited the studio in person. I don't think Nintendo will purchase early access to DLC but who knows Microsoft had good success last generation.

I suspect Nintendo is working very hard to get Rock star's support. Wii saw some support and I am betting Nintendo will get 3-5 titles ported before next generation systems fully take over leaving Nintendo once again technologically behind. Though Nintendo appears.to be future proofing WiiU they hired the guy from Crytek who ported CryEngine3 to consoles. This leads me to believe Nintendo is making WiiU capable of receiving down graded ports from nextbox and PS4. So support from Rock Star could be essential to Nintendo's survival.

I really, really hope so.

They definitely should! again it would be the definitive version.. heres an early look!

http://www.youtube.com/watch?v=S05fWaaATU8&list=FL47Vwj7PnGgdyksqyIFXkEQ&index=14&feature=plpp_video

Sadly, that's filmed content and not actual Wii U graphics.

Third-parties will have a new goalposts set for next generation; it will be userbase first and then audience.
How do you create an audience without releasing game content? *shrugs*

If they want their projects to be as profitable as possible they'd better port it to all consoles (PS4, WiiU, Xbox1080).

Practically zero, I think.

As for the OP, I wouldn´t be surprised to see GTA V on the Wii U.

I´d say around 70% chance of the game releasing on Wii U...though I´d say around 50% if we´re talking simultaneous release.

Why would I buy a WiiU for GTAV when my PS3 or 360 can play it?

You wouldn't. GTA V is just a bonus.

I would imagine that it would come out for wiiu, but i don't think that they will innovate much on the unique controller, since that might upset Sony/Microsoft for "showing up" their standard versions.