I'm concerned that Ballmer's overly nebulous meter for the "success" of W8 will ultimately lead to the irrelevancy of the Windows franchise. I don't want that.
Huh? In what possible way can a marketing definition of "success" possibly make Windows irrelevant?
I'm pretty sure that, internally, there are a whole bunch of KPIs that strictly determine what will or won't constitute success not just for Windows as a whole, but for the various subsections of the ecosystem too. That's not the information you share with the world though, regardless of which way the outcome goes.