He had one or two outstanding seasons for Rennes, where he run the show. The biggest buzz around him was how he found and made space effortlessly. Defensively, I'd say he was similar to Nigel De Jong, but a better passer than De Jong. His last season at Rennes he seemed to get a bit primadonna-ish if you like, not in a showboaty way but in a 'I'm not chasing that', kind of like Ronaldo when the ball doesn't go into his feet. I think this put Arsenal off and if I'm not mistaken, the only other club in the running for his signature when he left Rennes were bad-egg QPR.
He needed that move, the next step/level in his career, the last season at Rennes for me, was like watching a bored/frustrated player who was a cut above his team mates, rather than him being snotty. The problem is, he chose the wrong move, he probably has/had a dickhead of an agent.
It's make or break time for him, he really has no choice but to keep his head down and work hard, or he'll drown. If he works hard, keeps focus and rediscovers who he was a few years ago, he'll have you lot singing songs about him for years to come.