This has been a good read. Nice posting, OP.
It got me to thinking about the next stage of fighter aircraft, the unmanned fighter.
The human component is the limiting factor in current evasive and combat manueverability, with a practical limit of around 9G's.
We can easily construct aircraft that will do 16~20 G manuvering, but that takes the pilot out of the game.
What if the OP's 747 is a launch or control platform for some medium range, smart robotic aircraft that can super-cruise on out to meet the enemy, out manuever them, and launch a few short range high speed missles? Put the forward controllers in the 747.
that keeps the human casualty rate down, if you can indeed "control your airspace".