In future, it’d be better if the Devs didn’t sneak in BR changes like this. The dedicated BR change lists that give the community a chance to give feedback actually work quite well - and recently player feedback has been well received (i.e. A-10C, F8U-2)
We had no opportunity to give our thoughts on these changes - and neither seemed so urgent that they needed to be done immediately.
The J-7D was in a good spot, perhaps a little too strong. The J-7D has an airframe comparable to the MiG-21MF, however it carries much stronger armament in the PL-7 (Magic 1 equivalent) and PL-5B. This aircraft being 0.3 above the MiG-21MF was already a little questionable since the armament upgrade is quite significant - being the same BR is a little ridiculous. In the past the J-7D has struggled, but this is because it was 11.0 BEFORE the decompression changes, the decompression helped it tremendously since it didn’t actually move, and now it is to my knowledge the only jet at high BRs to sit at a lower BR than its initial BR pre-decompression.
The same is sort of true for the J35XS, although there is more of a case for moving this down. The main factor here is the very limited countermeasure quantity. The Draken airframe is also not particularly excellent now. However this is still a fast and manoeuvrable plane with 6 AIM-9Js, and it was surviving well at 11.0. Imo this change was not needed - certainly not so desperately that it needed to be posted without feedback.
Both of these changes are moving planes with strong IR missiles back into a BR region where the majority of vehicles lack countermeasures. This is not desirable.