That is what they call a QB that panics and runs away instead of stepping up in the pocket. It is not a talent, it is a lack of courage. If scrambling QBs were all that great, then everyone would have one, but they don't. The great QBs all stood tall in the pocket under pressure and delivered the throw, not run away and slide two yards short of a first down!
You can take Vick, McNabb, Culpepper and all those scrambling types and keep them! Give me Marino, Aikman, Elway, or any one of the modern day greats. They could run, but didn't. Well, OK, Marino couldn't run, but he could throw like no one else!