The Chairbacks are the only seats that should be assigned seating. This keeps the priority points system in place for the donors.
The rest of the arena should be GA, priced by section so you can purchase tickets at the price you can afford. Your price for the section you want would be a base price. You then get a discount for 1-donation level, 2 - discount for young alumni that goes down every year you are out of school, 3 - discount for active students, 4 - discounts for purchasing season tickets to other sports.
Keep sections 18-21 students only. The rest of the arena would be FCFS. This allows the students to buy premium tickets at a good price. Student ID would be required in this section. You also get the best fans closest to the action because they will be the ones who are willing to show up early to get the seats they want. These are the fans that make the most noise. Keeping them closest to the floor will make the entire arena look crazy.
Keep one section for day of game walk up tickets. That would make tickets available to everyone. College athletics should be available to everyone.
Just some thoughts. Begin criticism now.