I am so happy to see that people really like using the Gamepad. I only know a couple of people who own a Wii U, and they tend to complain about the Gamepad - and the Wii U in general. My friends are gits, essentially.
I personally adore the Wii U, and I love, love, love the Gamepad. Playing Legend of Zelda: Wind Waker HD with the Gamepad was magnificent, in particular - having the ocean map and item screens there in real-time was just so good.
It'd be great to have the option to play off-TV just on the Gamepad, I'm sure I'd use that, but my ideal would be to have the collectibles listed on the Gamepad - I'm picturing Banjo Kazooie, you'd have your jiggies, Jinjos, notes, honeycombs, feathers, eggs, everything on the Gamepad screen while you play so you can keep track on the fly. Ah just thinking about all this is so exciting, I feel like a kid again.
I haven't used the Pro Controller much - I'm always Player 1 so I get the Gamepad

- but Pro Controller support kind of seems like it has to happen too. It'd just make sense.