Can't see him leaving Arsenal, as much as he wants to leave and as much as Barca want him, I just think they'll end up getting him when his contract runs out.
I reckon Arsenal will win their battle to keep him , but leaving him with the raging Arseholes leaving Arsenal unable to selling him for anywhere near that in the January transfer window.
Barcelona would be mental to spend more than £20m on him as he just won't be a first team regular next season. Perhaps in years to come but not yet and as they are always struggling with cash they'd be silly to spend £30m plus on a substitute
I think he is an ideal signing for a team that has been fortunate not to have lost Iniesta, Xavi or Messi for any great lengths of time to serious injury. It will enable them to rotate their squad much more effectively than they currently do without weakening the team. I could see him keeping Pedro out of the team, or even Villa if they play 4-3-3 like the Cruyff days. He might not line up in their absolute strongest starting XI, but he'll play a lot of games, shit me, Mascherano played almost 30 times for them last season!
They'd be far better off without him. He's injury prone & his head has been turned what's the point in keeping him?
The only issue would be Wenger appeasing the fans, Its unlikely to happen but to keep the restless gooners happy he has to reinvest that money in a player of similat calibre.