I don't see how adding a little extra info on your tablet or smartphone exactly makes it revolutionary.
The Wii U and Smartglass are different, yet similar the way I see it.
Wii U and Smartglass both allow you to see extra details for the games you are playing, maps, info, etc.
Wii U however allows you to truly interact in real time with people, the game, and the extra stuff.
I've been looking into Smartglass, and whilst yes its a nice addition, I honestly, without sounding too much of a fanboy, don't think it's comparable to the Wii U's gamepad in terms of what it can actually achieve on and off games
Considering I've been playing Video Games since I was 3 years old, I'm still pretty terrible at them