Some more information:
According to Wikipedia there are currently over 350 developers working at Nintendos Kyoto Software Department, which are spread out between the 5 different Development Groups, this means we can probably assume that less than 100 are working in the Zelda group, the groups are certainly helping each other out in some cases but I'd be highly surprised if the other groups aren't busy with their own game developments as well. Now like I've said in the OP, Group 3 has released 2 Zelda games this year already, Wind Waker HD reportedly took 6 months to make and A Link between worlds had been in development since 2011.
This means that only just now all of Development Group 3 has started working on the new Zelda U, now if that game is going to have the same art direction as Wind Waker then yes, I could see the game being ready next year, but let's be honest, the next console Zelda will probably have a more mature look, I'm pretty Nintendo has noticed that those do better on their home consoles. So I still really don't see a mature looking console Zelda with HD graphics releasing next year.
