All aircraft speeds are abstracted, otherwise a MiG-29 wouldn't be flying at 900kp/h, also remember that any speed buff comes with a hefty Rate of turn Nerf, and I don't know about you but I prefer a good rate of turn to a good speed, also I love my Su-22 and Su-7 lines, don't touch them (except maybe a payload buff)
Then It would be even more unrealistic since Su-7/22 werent designed to be maneuverable.
If I wanted a good turn rate I'd choose the Su-25 and no the Su-22 as it is doesn't come with good turn rate. Besides These aircraft served a different purpose by design. One is FAST, while the other(Su-25) is SLOWER AND ARMORED. There's no logic in making an aircraft designed to be supersonic the speed of something designed to be subsonic and maneuverable.
If the tornado will be much faster than the A-10, then so shouldthe Su-7/22 be much faster than the Su-25.