Phase 1: Replace the East stands and fill it entirely with seats. Add press boxes to the top. Put the visiting team coaches boxes up there too.-- I don't care if the press or opponents have the sun in their eyes during afternoon games.
Phase 2: Renovate the South stands. They will remain bleacher seating but it will be expanded to take over the parking lot to create an on-site hosting facility. The donor "tent" food services will move to this facility, along with a new Cougar Club room, the band practice room, a football Hall of Fame and a BYUtv studio.
Phase 3: Renovate the West stands and fill it entirely with seats. Convert all of the press boxes to corporate/luxury boxes. Create a more modern 'face' for the stadium.
Phase 4: Renovate the North stands with the biggest (freaking) HD screen we can afford. The existing screen can be moved over to the South stands to 'double' its size.