I'm hoping it's far from final and can support more than one screen controller...I'm sure I could live with scaled-down graphics for that smaller screen, like, say, GameCube graphics. Depending on the game, you probably wouldn't need much on there if it was multiplayer, like on the original Final Fantasy: Crystal Chronicles where someone has a map, another has radar, etc.; I don't imagine it would be like four or five separate equally high-res views of different rooms, kind of thing.
And I think it's kind of hard to say we won't be using the features on that screen...wouldn't that be like saying you'd play a DS without using the touch screen? I'm sure Nintendo will make games that utilize it fully.
And you won't necessarily have to be drawing...though I do think it's funny that there's that uDraw tablet thing for the Wii... Wii uDraw...yeah...
Heck, any ideas used on the DS could be migrated over to full console games. They could even make a DS Player (like the Game Boy Player for the GameCube), and if 3D TVs ever get popular, I'd imagine they could make a 3DS Player too - though maybe they won't, as portable games seem designed more than ever to stay portable (with things like StreetPass). I guess Sony is remaking PSP games into PS3 games, and I think that's a little different as those are remakes/rereleases, but who knows? At least the option is technically there if Nintendo wanted to make portable games playable on the big screen again, just don't expect to StreetPass.
One easy thing that might work, and could be cool if a game is really cinematic, is to keep all the HUD stuff on the smaller screen. If players get used to glancing down to see their health/ammo, etc., spectators could be treated to a full cinematic experience by watching the TV. Of course, sometimes seeing how much health and ammo you have left is part of the excitement...but perhaps you could have, say, a fighting game from a traditional perspective, but on the big screen spectators can be treated to different camera angles as if it were an action movie.
EDIT: After reading some more it sounds like the Wii U is designed with only one screen controller intended at a time, as others have mentioned already...phooey. But at least I won't have to spend a ton on new controllers since I already have four Wii Remotes with MotionPlus (two built-in). But that golden Wii Remote being released at the same time as The Legend Of Zelda: Skyward Sword is tempting...it'll look great with the golden Classic Controller from GoldenEye.