If you're launching a payload that has long range in its own right, why do you need long range for the mothercraft? The payload travels faster and further than the mothercraft, so you want to launch asap after takeoff.

You do need reasonable range to stage to the desired launch location, I agree, but this would primarily be a "ballast" flight (empty) to pick up the payload from where it was assembled or stored.

And you need quick turnaround so that a few mothercraft can launch several salvoes in short succession.

So what you need to maximise is simply:-

(max launchable payload)/(runway requirement)

and clear some hurdles for loiter time with load, range without load, and turnaround time. Plus capex and opex.

There may be safety limits on where you can launch from and which parts of the trajectory cross inhabited areas, hence the concept of launch over the ocean to avoid dropping things on people's houses, but if the whole aim of the thing is to drop big things on somebody else's house (or office, or weapons lab, or reactor complex), then slightly different rules apply.

(I can. however envisage situations such as anti-satellite operations where you need to launch into a specific orbit, which requires you to fly to a specific launch corridoor, which may not be conveniented sited relative to your base. If you're in a hurry, you do this with in-flight refuelling. if not, you stage to a more convenient location for the launch corridoor and send the payload by cargo plane then load up and fly the mission)