I think there needs to be a Phantasy star game for the wii u, but not necessarily PSO2. The options presented with the touch screen are really appealing:

-Chatting with the touch screen and stylus(anyone who plays phantasy star zero will tell you how awesome that is)
-Using it as a more intuitive way to create/edit your character
-Free-aim shooting with the gyroscope for rangers
-Map display
-Quick access menu for items

There are so many things that can be done with the wii u controller that it seems like a bad idea to NOT make a phantasy star game for the wii u.