I'll bite.  The team has not yet come off probation (not until February).  Shula took over after spring practice, which meant his first season should be disregarded.  He had all of fall practice to implement his new season, and a 4-9 record is about as good as you can expect under those circumstances.  With scholarship limitations, depth is an issue.  Mix depth problems with injury problems (of which no one can foresee and no one is to blame) and you get a pair of 6-6 seasons.  When he had a senior-laden team and some depth, he wins ten games and the Cotton Bowl.  

He had a 26-23 record over his four seasons, of which 14 of his 23 losses were by one score or less.  Coincidentally, 14 of his 23 losses were to teams ranked in the top 20 at the time of the game.  If you ignore his first season, considering it a loss from the beginning due to how and when he took over, he went 22-14 and has set up this team to really compete in the next couple of seasons.  

The fact that he didn't beat Auburn or LSU or win 9 or 10 games in back-to-back seasons is the reason he was let go, and to some that might seem unreasonable.  It has nothing to do with the Bear, it has everything to do with impatience.  Where is my folly?

...Arkansas (had the game won, thrice!) but lost because we played for a field goal with a kicker that had already missed twice.  Tennessee, but lost because we couldn't score from the two yard line.  Mississippi State, but again the offense was unable to move the ball when it mattered most.  Auburn, but again not being able to score in the red zone and indecisiveness in the coaching decisions gave Auburn every ounce of momentum.  It isn't unreasonable to expect a head coach to win games he's supposed to and a few he isn't every now and again.  Shula has shown that not even the gimme wins are gimmes for him.  It's not unreasonable to expect a head coach to be able to get his teams prepared for every game, but the Duke, FIU, and Mississippi State debacles showed his lack of ability to prepare his team and come up with a viable game plan week in and week out.  It's not unreasonable to expect a head coach to make adjustments, if not during a game at least as the season goes on, but Shula proved time and again that he was either unwilling or unable to make any changes in his coaching philosophy.  It is not unreasonable to expect a head coach to realize that certain players (Chris Capps) are unable to do their job on the field and remove them, but Shula insisted on starting Capps against Auburn and gave up two sure scores to the Teagles because of it.  These aren't unreasonable expectations for any head coach anywhere.  The fact that we are 6-6 when we had a very real chance of being 10-2 if only the offense wasn't so miserably terrible isn't unrealistic.  Any decent offensive mind would have been able to go 10-2 with the talent at Alabama, but instead we got stuck with the "three up the middle and a field goal" time and again.  So I don't think our expectations of Shula this season were unreasonable.