NC State over Villanova is not even close to as big of an upset as UAB was over ISU IMO.
You may be correct. Seed-difference is one aspect, which would give the nod to UAB ... only "balance" on that would be that a 1 seed is expected to go at least four rounds, a 3 only 2. But other things in favor of your argument:
1. Possibly over-seeded team in bracket placement. Villanova may have deserved a 1, but maybe not in the second overall position.
2. N.C. State at an 8 from a power conference (and one with a lot of power at the top) and NC State was a big win/bad loss type of team. If the upset came from a high-mid like San Diego State or VCU, that might "feel" more surprising.
3. UAB was auto-qualifier from a one-bid league. There were I think four teams w/ 12-6 records, and UAB got to host the tournament. But ISU was second in a 7-bid league and also won its conference tournament.