On the weapons front, I think they have a clear vulnerability in that they're fighting like a conventional military. They're not fighting like an insurgent force. They're using tanks; they're using Humvees; they're using heavy armour, and they don't have an industrial base to replenish that. That's one reason that air strikes have been fairly effective.
I'd say that one thing that can be done to further speed up their decline in that regard is to change the targeting of air strikes. Right now, air strikes are focused one, on senior leadership, and two, on kinetic operations by ISIL. If we were to target tactical leadership as well, that would help to accelerate their decline in that regard.