On the one hand I don't think his value ever rises any higher than right now, however, if he gets his mind right under Rafa and gets some of his inconsistencies coached out of him, my word.
By the way he went from being managed by some chap named Alain Casanova at Toulouse to Alan Pardew and his s*** crew of assistants to McClaren and co. here.
He's literally never worked under a proper club manager or set of coaches outside of his international setup at France under Blanc and Deschamps.