It all depends on how you look at it. I believe he's done a good job here so far, so I think of him as a good coach. And when I hear arguments like yours, I just think, "Yeah, well its gonna take more than one fluky year to make me change my mind about the guy."
You're obviously not happy with what he's done here, as you're holding his lack of a playoff appearance in his first 2 years here against him. How you expect him to get into the playoffs while Larry Tripplett is a starting DT is beyond me, but you are definitely entitled to that opinion and I respect it. So you look at it the opposite way: when I type what I typed in the first paragraph, you're thinking, "You've got it backwards, buddy. One winning season isn't going to make me think of this guy as a winner." When, from my perspective, he already IS thought of as a winner, because for two years running he's won more games than he should have.