The WiiU is significantly ahead of the Vita aligned launch. Even with Nintendo's conservative estimates it will be ahead over 1.7 million units for 29 months. I'd think it quite plausible, aiming above Nintendo's expectations, it'd be well over two million ahead for first two and a half years.
I don't think Vita will have the legs of the PSP in Japan (PSP only sold 35% LT in 36 months, I think Vita 50% LT in 36 months is more likely and even generous. I guess it could, though.)
Even if leg ratios somehow match PSP's outside Japan (Why in god's name should they be anywhere near that high? I'd need to see massive curveball to say it could.), we're looking at sub 16 million LT for the Vita. So Vita's probable best case is I think WiiU's probable worst case.
For Kinect who knows... it'll have almost 5 million pack in users, but it would still need to sell 8-10 million solo to start beating the Vita for sure. I think that's best case scenario for it. I can't see why people would go out of their way to buy it.
