The Pentagon’s cost assessment office needs to reassess its F-15EX findings

I disagree. CAPE knows more about the actual combat capability of both airframes than the author. If you ever attempt to get an F-35 to carry as many weapons as an F-15, you will have a non-stealthy (external hardpoints carrying weapons are not stealthy), single-engine, short range pig of an aircraft. The fact that the F-15 was originally designed in the 1960s is a red herring. The original design (the structure itself) is solid, and all the guts have been replaced several times over, including all the best sensors and offensive/defensive suites. Long range, high speed, and proven air-to-air supremacy. And, since the development of the F-35 began, we have learned that stealth is not a panacea for air combat.