Here is my theory.
Miller and Libby had the same source within the CIA that was opposed to what the Plame/Wilson cabal was up to.
Libby and Miller are protecting that source.
Fitz gave up trying to ferret that source out and has no interest in going after the perps on the other side.
The Bush Admin is hestitant to take on the Plame/Wilson cabal directly for fear of having the MSM attack such as retribution.
But Goss will quietly uproot them over the next three years. That's how such things are normally handled when it comes to spooks - quietly, behind the scenes - and IMO Hoagland's column in the Wash Post yesterday was something of a green light to do such. The Plame/Wilson cabal broke that unwritten rule, and will eventually pay for it. But I doubt we'll ever have the satisfaction of finding out how.
I like your theory :). I think the rats were highly PO'ed that Porter Goss was appointed to run the CIA, too. For some reason, they fear him, just as they fear Bolton in the UN job.
The rats have something major to hide. It is true...we may never know all that is going on behind the scenes in Spookville.
However, it's hard to tell which third is which. Which, IMO, was intentional.