Appreciate you continuing to actively look for suggestions. Here are some thoughts for you...
The biggest single thing that will increase football attendance is putting a better product out on the field. The last few seasons, even with a relatively competitive team, there have been a lot of poor performances at home. Even when they win, they tend to play pretty poorly (think Toledo and Villanova). And the offense, other than that one magical 2013 season, has been consistently bad. Most people like to see high scores games, an offense that puts points on the board and is exciting to watch.
But far more important than style of play, the team needs to win. A significant percentage of the possible audience just won't support a team that does not consistently win. I know this is out of your control, but it is the biggest factor out there, based on my interactions with the community.
The second biggest negative/problem to overcome is making access to the Dome easier. I know a lot of people that would like to go to the Dome, are big fans, have the money and the inclination to be season ticket holders, but do not go because they can't afford parking that gets them close enough to the Dome to make for a walk they can handle, and are unwilling to shuttle. They tell me the walk from Sims to the Dome is too long, and they are too out of shape or too old to do it anymore.
This is the downside to having a stadium on campus, where it is difficult to provide mass transportation to people with issues walking significant distances. Even walking a couple of blocks up a hill can be tough on a lot of people. When I ask people why they don't go to games, this is the second most common answer.
I don't know that there is an easy solution. The Dome's location makes it really tough to provide easy access to a lot of people. I see busses for people with disabilities that drop people off next to the Dome but the people I am talking about aren't disabled. They just can't walk the equivalent of 5 or 6 city blocks to get to the Dome, and back again afterwards.
Don't think it is a big driver, but the food choices, even with one stand selling loaded nachos and another selling chicken tenders, onion rings and sweet potato fries, are not good. The best stadia I visit on road trips I make feature food native and special to the region they are in. There is nothing like that at the Dome. Everything is generic and can be found in just about any other stadium in the country. Would like to see things like salt potatoes, chicken riggies, coneys, fried haddock sandwiches, spiedies, chicken wings, apple fritters, cider donuts, half moon cookies, and of course, Dino BBQ.
If it is not possible to prepare some of these things in the Dome, I like the idea of allowing people to leave the Dome during the game and get food outside, where restrictions on open flames, etc. can and should be relaxed. There should be sufficient room outside to set up seating areas, and even set up mini restaurants. Wouldn't it be great to have a mini Dino, Pastabilities, Avicollis, Clarks Ale House, etc. right outside the Dome? This would also help address the problems with congestion in the Dome concourses before games, during halftime, etc.
Pricing for season tickets has been horribly screwed up for decades and needs to be addressed. IMHO, the thing to focus on for now are the number of people in the stands, not the revenue coming in. Lower prices for the best seats, give a graduated break to people who purchase season tickets based on how many they buy, and make it clearly cheaper to buy season tickets than to buy tickets to individual games.
And one other thing: ginger ale should be available in the Dome.