Its called balancing. Pl12s are nerfed and thats a good thing, its a matter of fradually introducing better and better missiles so that the game doesnt implode. When other nations get equivalents they will be buffed. Youre essentially complaining that the game isnt power crept into oblivion. You will get your modern flankers, you will get j10b and you will likely get j20 one day.
China is a very strong nation but there needs to be gradual improving of everything cause were still only 14.0.
I do compltely agree that a chinese 14.0 should already be ingame but china isnt weak. Pl12s are strong even nerfed and the j10a is also very strong