Kipper was the model of inconsistency. He had the ability to be absolutely godly for stretches, yet he would have periods where he was pretty bad (for his standards, bad was basically average). The big issue I had with him is that he never put up a good season while the team was doing well offensively; whether that's due to bad luck or whether he was actually unable to perform well in a system that wasn't completely defensively-oriented, I don't think I'm qualified to say, but I do know he was single-handedly responsible for the Flames' playoff failures for multiple seasons after 03-04 where he was one of the two primary forces that got them to the finals.
His faults were easy to overlook because his agility and his ability to make inhuman saves were unparalleled, but he was a very imperfect goaltender. He did let in some soft goals, and he wasn't as reliable as people seem to believe he was.