On the original subject of fuel fraction: It would be interesting to take a look at the numbers, but if I had to guess I would say that most supersonic fighters have a clean fuel fraction not far off 0.3, and that this number hasn't budged much since the F-4.
The exceptions I can think of are the F-35A/C, the Su-35 (blended), the F-16XL, and the Mudhen with its CFTs.