I have to air on the side of "No" on this one for some of the reasons already stated. I'll never forget feeling that I wanted to sign him from Monaco after they knocked us out the Champions League, when he was like 17/18 and bursting on the scene.
However, what a dick move this is after the Real Madrid fiasco in the summer and the bending over backwards the club did to get him nailed down. I'm assuming Messi is away at the end of the season, or he knows of forthcoming changes he doesn't like.
Regardless - no thanks, don't need that attitude and ego in the dressing room here.