Katushiro Harada, a producer for Tekken has provided a progress update for the franchise on the Wii U:
For Wii U, at the moment, the core members aren't really assigned to that yet. We have a different group outside the Tekken Project within our company that works on advanced technology. So that section is currently evaluating the hardware and the specs, and what would be necessary to create a Tekken on [Wii U]. Once their evaluation and research is done, they'll kick it to us and we'll start laying out the specs for that. But we're not at that point yet.
It may not be a ton of movement, but at least something is happening.