I don't think Cahill is better than Kos though, but even if that should prove to be the case it wouldn't solve a single creative issue in this team. And that is what's going to cost us points this season more than anything else.
I gotta say I find it extremely worrying that we're heavily rumoured to be in for a defensive midfielder and a centreback at a time when we desperately need a playmaker and a wide forward. It's the kind of signings we could have done with when we still had Cesc and Nasri around.