I've been impressed with the results lately. I think most people understand that in the NFL, you can't dominate like you can in college. You can't recruit anyone, and it is hard to tell if someone will pan out. Not to mention the head coach doesn't even have the deciding vote in who to draft in a lot of cases.
The Titans were hit with cap penalties a while back, and over the last few years people have expected them to win about 4 games, and I think some people predicted that this year as well. I think it is safe to say he has definitely overachieved over the last 3 years.