I think the way he was fired was bad. 9-3 season isn't good enough? I think that's a very decent record, and I do believe he started trying to change things when they weren't working (i.e., going to more of a spread option, hiring Pelini to take over defense...just to name a few) unlike certain other coaches.
But I would definitely say no, we should not have fired him. Steve seemed to have no game plan on what type of coach he was looking for, and out of desperation he settled on Callahan. The whole process was a complete joke, and was handled horribly by Steve. Bad, bad, BAD!