Thread title is a bit misleading. He hasn't agreed to move to MCFC at all. He's supposedly agreed a contract offer, but no transfer fee has been agreed between clubs. It's not a done deal. I'm not even sure if the contract thing would be legal, I doubt Arsenal have agreed to let him negotiate with us whilst he's refusing to negotiate with them.
Either way, still really do not see this happening. The only way it's happening is if at his age he's now happier to be better paid and potentially end his career with a winners medal whilst NOT being top man at the club, because rest assured there's no way we'll let Aguero or Balotelli play second fiddle to a near 30 year old, it would make no sense what so ever. He's got to be happy playing Dzeko's current role, no guaranteed starts. Which frankly for someone of his quality would be a waste, especially if the contract makes him the best paid player at the club. Not that that would even be a remotely sensible thing to do either.
He's having a fantastic season without a doubt, but he's also had plenty of seasons where he's given adequate reason NOT to put him on an insane contract. No-one likes paying players to sit on the doctors table. You would offer him Arsenals top ceiling limit + 20%, as long as that puts him under what we pay Aguero. There are two players you would bring to the club and make them higher paid than our highest earners. One is Ronaldo, the other is Messi.