I think I would rather have 18K-22K seat stadium with all the amenities and upgrades that a top D-1 team or NFL stadium has than 36K seats of which only 12K-15K are being used.
Things to include:
More/upgraded restrooms
More/Nicer concessions
Spirit store/merchandise
Suites for big alumni
Video boards for replay
Video under the stadiums for those in a line at restroom/concession
Enclosed Concourse
I know some of these things are planned, but that's what I would like to see.
And like UNT said, just win! Winning takes care of a lot of problems.