OK, I'm about to save the State a lot of money:
1) Civil - Paving, walkways, underground utilities. They're fine. minor and spot maintenance fixes only.
2) Architectural - After 20 years, the tower and some of the outbuildings probably need some roof repairs/replacements. Some of the entry/exit door systems may need replacements (non-security related). Interior finishes is decoration. Not spending a lot of time inside, it either needs a refresh or it doesn't, but it's not super critical in most back of house areas.
3) Security - Are we talking facial recognition, ticketing systems, lot cameras? Do we really need a huge investment here? Probably not. I could see upgrading that are vulnerable to online attacks.
4) IT, networking, video, and sound. This should be the main focus as ours were subpar on opening and even moreso now.
5) Food service equipment. Depending on replacement cycle, it may be at the end of it's service life and an opportunity to enhance the fan experience. Need to huddle with the operations team on what their model will be going forward. Continue with generic stadium fare or franchise out the venues that will customize space. Given the number of dates and attendance, I'm ruling out the latter.
6) Field - turf, irrigation, and drainage. The field is fine anything above regular maintenance is a waste of money.
7) Field and parking lot lighting. I'm sure there are some lot lights that need replacing and perhaps a dark zone or two given the number of configuration changes over the years, but this should be minimal. We don't use most of the lots anymore.
The field lighting is another story, it sucks, as if they ran out of money in 2003. Time to fix it. This is probably one of the most bush league aspects of the Rent and has been for a long time.
8) MEP-HVAC. There should not need to be major upgrades here unless things are broken. The energy audit is likely driving this. A hard look as the cost savings of an upgrade is necessary.
9) Life Safety - Emergency power, fire alarms, sprinklers. Whatever maintenance is necessary for code compliance. This should not be a huge refit.
10) Elevators. Same as 9. Shouldn't need more than regular maintenance.
As for operational efficiencies. This isn't necessary, we won't have to deal with large crowds in the near future so anything learned would be theoretical. If this is about how to use few people (or fewer concession stands) due to the reduced crowds, people need to be fired. They don't belong here.
If you want to pay me to do a walk through to point out specifics, I will for a nominal fee. Tell me where to send the bill.