Jeremiah Slaczka, Creative Director on the Scribblenauts series and co-creator of devs 5th Cell, has reportedly revealed on NeoGAF that the Wii U has no "system-wide" achievements system.
To be exact:
There are no Wii U accomplishments that are system wide. They are up to the developers to include or not include. Scribblenauts Unlimited loosely has them in the form of "Global Starite Shards" which is like a giant checklist of global things to spawn and do in the game that aren't area specific.
The news comes via CVG, though it's unclear how the site can be sure that the poster in question really is Slaczka. Regardless, would you like achievements or an equivalent system to be added to the Wii U after its launch, like what Sony did with the PS3's trophies?