This has been a long time coming. I am happy to see the implementations of HTML5 technologies that are capable of delivering this kind of experience.
1) security 2) computational performance 3) flexibility
WebSockets for example are just a bad rehash of existing APIs. Woopty-doo.
this is a great DEMONSTRATION. leave it at that. if you are really that annoyed by the points you mentioned, why, it's open source!