The question was roles not covered by the F-22, F-35, and/or F/A-18, so that response isn't quite on point, even to the extent the F-15EX might also serve that role.

Nah, that's the F-22 and F-35.

This is the cheaper, "upgrade the old system" option.

And no matter what aircraft we buy, we're still in the AFG and Iraq, goin on near 20 years for the former. This is a drop in the bucket compared to what we're paying to stay in those countries. The medical care for OIF and OEF veterans will be north of $1 Trillion...

That's a better argument for the F-22/35 programs. The F-15 is a workhorse, and this is an extremely inexpensive upgrade program relative to building an actual modern replacement, or buying F-35s and calling it "good enough."