Most people don't think of Tebow & Leak when we talk about Spurrier's 2-QB system. They think about Doug Johnson, Danny Wuerffel, Jesse Palmer, Rex Grossman. Those years.
Tebow & Leak was really a one-QB system (Leak), with Tebow coming in from time to time almost as a Wildcat.
The true 2-QBs were those earlier guys.
Agree with some of what you said, but I think this part isn't always true.
Spurrier did a lot of things with his 2-QB formula. One was, he played the hot hand; one guy might be up, the other having a down day. Another thing was communication--back in that day, a coach often ran the play call in with a sub. Spurrier used his QBs as the sub. Say he had Jesse Palmer in for part of a series; he'd be standing there with his arm on Grossman's shoulder pads the entire time, talking to him blue blazes. And then he'd send Grossman in, with all that information about how to exploit the defense, and Palmer would come out. Spurrier would grab Palmer's shoulder pad, and off they'd go for another rapid-fire live action coaching session.
Point is, he had a lot of reasons for alternating QBs in a game.
Now, I don't know if almost every other team that has ever used a 2-QB system did it entirely to have a "runner" and a "passer". I haven't surveyed college football. You could be right that it's the most common reason. But it certainly isn't the only one.
I know this: if Heupel sticks with 1-QB, I'm with Heupel. If he plays with 2-QB rotation, I'm with Heupel. Either way, I'm with Heupel. He's our coach.
Go V