Would anyone be surprised if he bagged 30 goals a season playing for City or Liverpool ? Really doesn't seem a stretch to imagine it but I guess that's because his entire career so far has just been one giant goal scoring bonanza with no drops in form or injuries.
On a side note I've always been fascinated by how Aguero has never been seriously linked with a move away from Man City. He's obviously one of the best strikers in the world so you'd imagine some of the traditional big names would have shown interest during his time at City... but seemingly nothing, no offers, and he's never pushed for a move away from City either.