Does Natal need a controller? No, presuming it gets games tailored to it. Can it complement existing gamepad - sure, leaning in FPS, etc. all sounds fun as mooted by MS.
Would the experience be better with something like a Wiimote? Well, obviously the jury's out until it launches, but I suspect the answer is yes, if only for certain games.
My reasoning:
1) stand in your room and jump around and swing your arms as if hitting something using visual cues on a screen before you (that's Natal to be fair. It is. You see a ball come towards you, judge angle, etc. then swing you arms. Please note I'm specifically thinking of games where you'd hold something)
2) now repeat but hold any old thing that comes to hand as a prop. Did that feel better? It did for me. Holding something while swinging at an imaginary ball, etc. feels better than holding nothing. (that's Natal while holding a rolled up newspaper or a simple plastic 'prop' item)
3) now repeat with a Wiimote - feel the rumble and feedback? Felt even better didn't it? (that's Natal if it also had a dedicated controller with rumble feedback. Note that in theory gamepad could suffice but of course would face design/shape issues as the sixaxxis did/does)
Now I hope to see more than ball/bat titles on Natal (and Wii for that matter) but the fact is that for any game where you're supposed to be holding something actually holding something feels better. And holding something that can deliver feedback with vibration, etc. is even better.
So while I really hope for exciting new stuff on Natal, if it wants to deliver something like Wii Sports in a superior fashion then I honestly believe it needs a peripheral with vibration to hold in your hand.
For full body tracking and stuff that doesn't rely on holding something I think Natal looks awesome. But if there's supposed to be something in your hand then I think it's weakened because we expect to hold things in our hands, and holding something feels better than not.
Try to be reasonable... its easier than you think...
