Team Ninja, who is bringing Ninja Gaiden 3: Razor's Edge to the Wii U has shared that the platform is "very easy to develop for", which echoes what we've heard in the past. It was then elaborated that:
We’re finding it very similar to develop for Wii U as for the Xbox 360 and PS3. They’ve asked us what we would like to see from the hardware, and when we give them feedback we can see that they’re definitely listening to it and making changes. The hardware is still constantly changing.
It was also mentioned for the second time that touchscreen elements of Dragon Sword, their Ninja Gaiden game for the DS, will find their way into Razor's Edge on the Wii U, and it's also not ruled out that Dead or Alive 5 could end up on the system:
We’re thinking about all sorts of things. Right now, our Wii U development is focused just on Ninja Gaiden, but we’re definitely keeping other platforms in mind for DOA5.
And that's all sounding pretty darn agreeable to me.