I agree with a lot of what you said, PT. Vick is pretty similar to McNabb, at least in terms of mobility. Assuming McNabb goes down at some point during the year, Vick could come in, and Philly/Reid wouldn't really have to alter the playcalling too significantly. Assuming Vick picks up the system adequately, that can be a plus.
That having been said, I don't know that Vick can "develop" anymore. The guy was drafted, what, 8 years ago? This is just me talking, but at some point, I think you are what you are.