I do think he disproved the 'he can't pass lad' theory when he was at PSG like. He was never, ever bad on the ball and people really underappreciated how good his all-round game was as a midfielder while he was here.
I'm not sold on him coming back now, unless it's a very cheap, short-term deal. Not particularly because his quality has dropped off (it has a bit, but he's still better than what we have) but because of his age and the fact he's had a lot of niggling injuries while he's been at PSG. Still turned in some superb performances for them mind.
This is before the obvious off-field issue.