To the best of my knowledge, the F-16 was the first fighter to feature torsional agility (Though I could be wrong) which allowed a relatively light wing-loading to sustain high-G's more effectively at higher airspeeds than would typically be allowed without the torsional-agility.
I have a couple of questions pertaining to this...
1.) Was it possible to design an airplane with torsional-agility prior to the F-16 (Did the technology and construction technology exist prior to the F-16's program started to produce the desired result)?
2.) How much of an improvement does torsional-agility provide in terms of allowing a lightly-loaded fighter at high airspeed to avoid excessive speed-losses in sustained-G performance? Like 10%, 20%, etc?
3.) Does torsional-agility require an unstable airframe?