The only thing (as far as I can tell) that was delayed is the deadline for the Developer's Challenge. And that is because a major SDK update is coming very soon and they want to give developers more time to utilize it.
Precisely. They felt that it would be unfair, with a week or two left, to say "oh, and by the way, here's a major update".
It may be unfair to change the platform just before the deadline. Likewise, it is unfair to change the deadline. It looks unco-ordinated and it could run afoul of some contest laws. It would have been best provide a stable platform during the competition then release updates afterwards.