Nintendo made the Wii U available for Club Nintendo Platinum members to play last week. I attended!
The GamePad controller is light, easy to manipulate, and not as obtrusive as it seems at first. Ultimately, my fears about the controller’s usability are gone. Yet, based on the selection of games I tried, I fear that Nintendo will be the only company to ever use a tablet controller effectively, as was the usual case for the Wii and DS. We've already seen the DS introduce a second screen, and there's not much else that can be done here that the DS hasn't already attempted.
The GamePad does not need to exist. None of the games demonstrated a clear need for this controller.
The tablets' companion piece, the Pro controller, needlessly messes with standard controller layout. It swaps the positions of the right A/B/X/Y buttons and the right analog stick, which is not impossible to get used to, but it begs the question: Why? The same question applies to everything about the Wii U.