He's more talented, Cesc may have been a bit more matured, due to him playing for a team that doesn't have the luxury to have not given him 150 games by the time he was 21, just like Wilshere.
I'm not convinced Cesc was better anyway, I think playing in England at the time where players who can control a football and then move it at a good speed was almost a new concept still would cause such a response. This is like when Pep said how he has a few Wilsheres in his academy. I don't think Cesc would necessarily have been as big a deal in Spain, and hasn't been as big a deal since he has gone back there.
Don't get me wrong, I am a fan of his, and considered him as the League's best midfielder before he left Arsenal. That said, Thiago is certainly more gifted and to use Caf terminology, 'has a higher ceiling'.