The gamepad despite its size is quite light and comfortable.
And if you look past that touch screen, you have a traditional modern console gamepad. Twin analog sticks, a d-pad, four face buttons, pairs of shoulder buttons and triggers, etc. Everything is here that you're used to being here. The analogs even depress for R3 & L3 functions, although I've yet to ever need it.
The only thing somewhat unconventional here is the digital triggers, but it's not like we have any racing games here that could've put analog to good use. And for everything else, I prefer digital.
That said, touch screen gaming is largely worthless. So Nintendo's attempt to bring that "innovation" to consoles, despite it largely being overlooked on the 3DS now that everyone realizes its inferiority for most tasks, hasn't accomplished much on the console.
But I use it frequently for off-screen play. I like to lean back in bed and basically enjoy my Wii U like I would with a handheld. And on the rare instances where the touch screen is put to use, it usually actually adds to the experience like streamlining inventory control in Wind Waker HD.
And I suspect using it as a camera in the upcoming Fatal Frame 5 is going to be its best use yet.