I'd say...it depends.....
Is 8-4 with an Outback bowl good? Sure its good. I'm sure 85% of college programs would take that result in a heartbeat. So in the world of College Football, they probably earned a B or B+.
However if you compare Iowa to their expectations....Iowa lost all 3 games in which they were underdogs and lost a home game in which they were 10.5 point favorites. That in itself means they didn't live up to expectations. So that's like a C-
I personally give them a D+. If you go back and look at all 4 losses, Iowa was in each and every game until they made stupid and preventable mistakes (Stanley late INT vs Wisconsin, Stanley INT at goal line vs Penn State, 2 late RB fumbles vs Northwestern, bad pass defense/terrible 2 point conversion attempts vs Purdue). They also nearly let Nebraska beat them when they were up by 15. You could easily make an argument that this year had 12-0 potential. After seeing what Wisconsin did, this should have been AT LEAST an Indianapolis year. Iowa failed all around in those areas.