No offense, but I think that you're focusing too much on the play at one position: QB. Cody is more advanced as a passer, but BJax was a much, much better runner. I think we all know that to be true.
But if you look at the team as a whole, I think you'd agree that there are very few areas that aren't much, much improved from '06: the kicking game
, QB, maybe CBs and LBs.
Can you say that you don't think that the OL, DL, WRs, RBs are, at least from a depth perspective if not a performance perspective, much, much better than they were in '06?
I don't think that I've seen anything to prove to me that I can't continue the extrapolation from '06 out to '10 and beyond, but like I said: the 4-win jump from 6-10 wins (or even from 6-8 wins!) is infinitely harder than 2-6 wins and is bound to take more time.