JDAM is a good example - it's cheaper to circumnavigate the globe in a B2 than it is to launch an equivalent load of Tomahawks. Crusader would be the next step in cost savings, a sationary fire-base that could hit anything in a 60 mile radius at a much lower cost. Drop one off and resupply it once a week. I would think it would pay itself off in fuel savings alone.
A great deal of money has been invested in air superiority, but the fact is that turning the skies black with attack aircraft is an expensive business to be in. The possibilities should at least be explored.
I'm not sure how Metalstorm technology enters the equation. Metalstorm is a 'volume over substance' system, an 'area weapon' if you will. Crusader's primary role would be precision fire.
Imagine going back in time to WWII and explaining that we need artillery for precision fire and special automatic rifles for area suppression :)