TykiButterfree
Such a tease!
Apart from the two storylines already available on the Wii U, there are additional story missions which make use of the new Wind Waker-inspired maps. Those can be transferred to the Wii U version (along with the new characters) with a download code included with the game.
It's safe to assume that DLC will be made available without buying HWL, at least after a while.
I'll probably just wait for dlc then. I agree, they probably would release it for wii u after a while.