The thing that pains me about Nintendo's recent consoles hasn't been the system's power or engine support (there are some good looking games on it), but their continued choice to try and innovate the controller. Not only is it harder to use then the competitors controllers but it's caused Kinect and Move to exist and that annoys me to no end.
I think it's important Nintendo does try to innovate the input device for a couple of reasons.
1.) Nintendo needs to differentiate their console from everyone else's. Think about the consoles of past generations. They were usually different from one another. System A might have FM Synthesis, a faster processor, and a couple background layers, but System B would have real sound, a slower processor, and better graphics with rotation effects. This makes the games for each system a unique experience, often not possible on the competitor's. Nowadays, thanks to the standardization of graphics, sound, and controllers, consoles and their games are very similar to one another. Look at the 360 and PS3. Not counting the exclusive games, what's so special about one over the other? Many would argue that it's only worthwhile to get either or, since they share so many games and their performance is similar. (Some even add the PC to the list.) So let's put in the Wii U without the controller and 1st party games. What's so special about it? The thing that makes it special is the controller. A different input device will allow for games with an experience not possible on the competitor's system.
2.) Better input devices can make games better. Nintendo has been trying for years to create a great input device. They've created the d-pad and shoulder buttons, and implemented rumble, the analog stick, and the pointer in games. They've also introduced touchscreens for games in the DS. All of these have been released to gamers with praise, and are technologies proven useful in just about every game. Why should they stop trying to create new input devices, just because what we have is good enough?