USAF is Claiming That F-15s Have a Design Weakness, So We Need More F-22s

The alleged weakness appears to relate to potential potential failure of the F-15’s upper longerons near the canopy seal, basically the keel beams.

It may be true. It's also likely that it can be fixed with a doubler relatively simply, but the USAF, in it's never ending quest for more white elephants known as the F-22, is not going to do this.