Having a couple structures in the open corners of the east side would really be a great addition. I would do a simple facade on the exterior of the west side to give the stadium a bit more of a classic look. TCU did a great job of this on their stadium renovation. The enclosure would create some much needed gathering spaces that were protected from the elements for winter games and other non-football related events. The current cougar room is really a pathetic space for boosters to gather.
I would add more seats to replace benches and i think we'd find plenty of fans willing to pay an extra buck or two to keep the fat guy next to them out of their space. Capacity at LES is fine, it's the amenities and atmosphere that I'd like to see enhanced.