Make no mistake, Sinofsky does believe in Transparency. It's just that he is very cautious with respect to revealing information that may or may not be relevant in the context of reality (think WinFS and several other Vista constructs that never came to be based on the realities inherent in making quality software that you also ship).
We will definitely have IE8 coverage on C9, but only when they, the IE team, have realistic things to talk about that won't set expectations improperly....
I'd hazzard to guess that the IE 8 team is very busy at work on the next great IE. I'd also state that I have no real idea what they are doing, exactly, and that's fine. The point is, they ARE doing...
C