I'd think we would have a better chance of being the top ranked G5 team than winning the PAC10 or Big12 anyways.
It would be humbling if that happened, but I'd hope BYU didn't drop football, and just reinvented itself as it did in the 70's and 80's.
It would also be sad to realize that Bronco would be largely responsible for that demise as he has been at the helm for most of the years when things where happening (BCS era, conference expansions). (And I'm NOT in the "Fire Bronco" crowd)