I think people have been unduly harsh on Gibbs all the time he's been here, and it's probably because he's a big earner. But as was said above, he was one of the better players during the relegation season, and I'll throw in that he stuck out a mile in the Championship the following season. I remember games he terrorised teams going forward (and nobody covered themselves in glory defensively that year).
Of course it's come unstuck since. He's gotten older, picked up a couple of injuries last year, and of course that's set him back. I would also guess that when nobody came in for him after his first season in the Championship, he probably did lose something mentally. So yeah, the last two years have been poor, and he's only going to get worse in the future, but he hasn't been terrible the entire time he's been here.
He's still more naturally talented than Townsend, he's just shot it.