To be honest, I'm sure that I'd call the touchscreen revolutionary. It's a first on a console and it is innovative, but Nintendo are essentially taking something that worked well on the DS and implementing it into their new console. Don't get me wrong, I think that the touchscreen is a great idea, but I don't think it's revolutionary.
In my opinion, the Wii controller was more revolutionary, as it changed the way people play video games. Until the Wii, video games had mainly been about pressing buttons on a controller. I'd also say that being able to use the Wii U controller's screen instead of a TV screen is revolutionary, as it's the first time that console games can be played without using a TV screen.
While I agree that the Wii remote was hardly a useless gimmick, especially pointer controls, but I definitely think this controller is revolutionary. The DS screen was simply too small and insensitive, as well as limited to only one, plus it was stuck to the top screen. The WiiU's tablet, on the other hand, is large enough for a finger to use, which also allows more detailed things on the screen. The issue of sensitivity is solved as soon as Nintendo releases a pressure-sensitive stylus, which they no doubt will.
This solves two main problems with the DS' touch-screen. 1. Drawing. You can't draw properly without a pressure sensor... I'm not sure quite how much of a difference it makes, as I don't own a tablet yet, but it does make a large one. Think of how awesome your Mario Kart decal could be if you could draw it as if you were drawing on paper! 2. Aiming. While the DS' stylus could be used for aiming, as shown in games like Metroid: Prime Hunters, it created a huge issue: You lost control of half the controller. The WiiU Tablet would still have this problem... But it would be much better because you have the button inside the stylus! So rather than holding R to fire, you simply push down, leaving those buttons for less important tasks! And if it's a half decent pressure sensor, you could actually control how strongly you fire, such as using less water with FLUDD in Mario Sunshine.
Then there are two more things that the Tablet changes from the DS: Being able to have multiple Tablets/use other controllers and not being restricted by the 'Big Screen.' The first allows more detailed multiplayer gaming, the second allows special types of games, like the Wii-Sports-esque game we say in the trailer. I don't think I need to elaborate on them, as their usefulness is quite obvious
