No more than a passenger... in one of the best teams in the league. How are we going to sign someone who is at the centre of everything at Emirates Marketing Project??
The very fact we have a chance of signing him should indicate that he isn't quite good enough to hold down a first team spot at City. That isn't something to sniff at. He has been behind strikers like Aguero and Negredo for years, strikers who wouldn't dream of coming to Spurs.
When he does play, even from the bench, he scores goals.
Moreover, he is a far more complete package than Austin for example. If we are looking for a backup/competition/mentor to Kane, we really couldn't do any better in footballing terms.
In financial terms, sure, Austin may be the better deal. He would probably command £50k a week tops, although even in terms of a transfer fee, he would probably cost a similar amount to Dzeko.
Don't be surprised if Dzeko ends up at Arsenal or Roma (i.e. in the Champions League, and out of our reach).