John Boyd was the greatest fighter pilot who never got to fly in combat, but he never lost a dogfight and could get on the tail of aces in less than a minute. He argued that the F-15 was a great airplane until the Pentagon started loading it up with incompatible armaments ostensibly to make it a multi-mission aircraft. It ended up costing five times more than original design specs and was not great at any specific mission. Boyd knew the Air Force needed a fighter pilot's fighter and was the prime motivator for the F-16.
“Not a pound for air to ground”.
The original F-15 was PURE fighter/air superiority. It just got bigger because it had to get FASTER. In the air superiority mission, I’d challenge anyone to say it wasn’t great at that specific mission. I think it’s proved that.
The F-16 began life as a multi-role fighter. Not the fastest and it couldn’t get first look/shot/kill, but it was a hell of a platform.
The high (f-15)/low (f-16) mix worked well, but the while the F-16 is agile, it isn’t half the air-to-air platform of the F-15.