As long as MS provides an accurate target for developers to work with, delaying dev kits is irrelevant. As multiple insiders have said, it will be around E3 of next year before Microsoft or Sony would provide final dev kits anyway. So you're talking four or five months tops for devs to have access to final dev kits before launch, and a much shorter time frame to work with final dev kits as games are finished well before launch day.
lol @ Microsoft fearing NDA breaches because they have been doing it. Both companies have so many sources and information, there's no need for either to get people to break an NDA.