It seems I was wrong about the F-15X carrying 20 missiles. The actual number is 22. It'll also have a 20,000 hour service life.
With it's $27,000 per flight hour opreating cost, replacing F-15C/Ds with Xs would pay for itself in ten years.
20 missiles is still a
lot of AAMs. How many were fired in Desert Storm?
But lets sit and stink on this for a moment. F-15E has 1 pylon under each wing, 1 centerline, and 6 on either flank. So that's 15 potential places to put a missile. The wing hard points can mount
2 AAM's in addition to what looks like a fuel tank. Assuming the -15X would also want to carry external tanks, this brings us to 17 hardpoints. Historically, only two AAMs are carried on the flank hardpoints because of length of the missile and concern that the fins might hit something as its separating from the aircraft, but with more compact missiles like the AIM-120C, maybe 4 missiles to a side. That brings
down to 13. If they remove the AN/AAQ-13 Nav and AN/AAQ-14 pods, and install hardpoints instead, that brings us back to 15.
This image, from a questionable source, suggests that Boeing has been kicking around the idea of adding an additional pylon to each wing. If that's the case, this may not be hard. With 8 on each wing, and 4 on the flanks, that's 20 right there.