I know they won't, but they should approach those season ticket holders that Maniac talks about and ask them to relinquish seats they don't use. I am sure it would be a pain to mine through that data. I now get an email after every game that my tickets get used which says something like, "Thank you for attending!". The only game I could not find anyone to use my tickets (I almost always get them in someone's hands if I can't attend) I never got that email. So I know that data is there, along with what goes through stubhub.
I also see it from the mindset of, 'they bought the tickets so it is their right to do what they please with them.' Ticket holders do hold that right. They paid a pretty penny so I am not as radical as some on this site. That being said, there ought to be a way for people in the 400s, who give 1K - 5K per year, to move up during a 5 year span. But to Maniac's point, there 10+ seat hoarders who never intend to sit in them. So if that is the case then there ought to be a way to identify that and swap somehow.
I have 4 seats in the stadium so I am just happy to have season tickets and solid parking. But I know people who through season tickets, parking, other sports, and other donations have given around 6K/year since the renovation. That's about a 30K investment to not be able to upgrade once. I see it from both sides, don't know how to solve it, and am far from the smartest person in the room, but that just seems like a flawed system for a dedicated fan.