I just watched it, and more than anything, it seemed like it was slow. It seemed like he would swipe and nothing would happen, so he would swipe again, but it was actually just that the tablet was still processing stuff, so then it would eventually process both gestures. I think it would be quite normal for a developer release to be slow.
As far as your point about whether Apple would allow people to see this, well, that's just the Microsoft vs Apple marketing philosophy. Apple typically presents things that are very highly polished and nearly complete, whereas Microsoft says "Hey, check out this thing we're working on." All else being equal (I'm not saying it is, but if it were), they both seem like viable strategies.
As far as your point about whether Apple would allow people to see this, well, that's just the Microsoft vs Apple marketing philosophy. Apple typically presents things that are very highly polished and nearly complete, whereas Microsoft says "Hey, check out this thing we're working on." All else being equal (I'm not saying it is, but if it were), they both seem like viable strategies.