2) It'll innovate
This is the main reason this system is being made. Playing a title on the Revolution will feel completely new, whereas even the prettiest 360 titles already feel familiar. The visuals may be gorgeous, but so far the new console isn't delivering much in the way of new gameplay. You're paying a higher price for the same controller you've been using for decades, and gameplay experiences that reflect that.
The Revolution's unique pointer controller automatically translates your movements into game actions. Moving your wrist could swing a sword or flip a switch, or anything a developer might think up. Entire existing genres will be changed by this, with first-person shooters and racing titles leading the way. Even gun games, usually limited to the arcade for a real sense of accuracy and intensity, could make a comeback. All this before we even ponder the entirely new gameplay ideas developers come up with.
But don't worry, ports of PS3 and 360 games will still be possible thanks to the traditional controller shell, built to house the pointer and provide basic control. The Revolution's controller will slide into this (still unseen) device and combine motion sensitive controls with standard buttons. How well this fusion will work we aren't sure, but chances are ports won't be the focus of Nintendo's gameplan. For more of what you've already played to death, stick to Sony and Microsoft's systems. Hop over to Nintendo to get a taste of something new.
