...figured someone would argue that we've had "elite" QBs already, and I think some of those arguments are OK and valid for discussion. I think to get what the OP is asking you have to think about his question with respect to QBs that are a step above "elite", whatever you would call that. Think "Transcendent". Manziel and Tebow were transcendent college players (no statement made or intended about their professional careers). The Mannings (both of them, really), Cam Newton (ugh), Andrew Luck, etc... all the same. These are all guys that you build a program/system around... not ones that you fit into your existing program/system. They're all a notch above Elite. Maybe Transcendent isn't the correct term, but it's all that I can come up with.
I get what the OP is asking, and I do not believe we've had a QB in my 40+ year lifetime who is in this category. There aren't many around. There isn't necessarily one in the country each year. I hope we have one or two on our roster right now!! I'd really enjoy seeing that.
Maybe my statement above is another way of asking the OP's question... if a QB were talented enough, would Coach Saban change his system to accommodate the skillset of the QB? I think "yes"... look at Amari this year. He let CLK turn him loose.
I think the closest we've come was Brodie Croyle. With a different coach/staff/system (including strength training) I think he could have been really special. I have often thought that he could have put up some big numbers under Price, but we'll certainly never know.