Here a thought I had lately about an idea for the next gen. It's not Nintendo specifics:
USB ports for the controllers. Yes, I know, the horrible PC/console merging sucks, I agree, but think about this. Consoles can't do certain things as well as PCs. Such as what? RTS for example. So imagine, all you have to do is plug your normal USB keyboard (most are nowadays) into your system along with your mouse and BAM. Or they can sell special specific mice, but they'd be cheap! It's just an easy way to expand controller capabilities.