I guess a lot depends on how stealthy the J-20 and PAK-FA will be. As a first attempt at stealth, they may not be any better than an F-117, which isn't much better than a EF2000 or Rafale from some RCS figures I've seen banded about (all between 0.025 - 0.1m2). What was classed as a stealth plane 20 years ago, wouldn't be one today. Unless the RCS falls under 0.003m2, it might not even be correct to class them as 5th gen fighters.
If they have 1700 F-35s, then problem solved I guess.