The primary problems that the Chinese are having with the ws-10A are the thrust generated by the engine and the engine life time. However I'd think that more research will be dedicated to this field since China couldn't develop her own 5th generation fighters without a decent engine. Imagine being able to produce your own stealth fighters but still relying on the Russians for engines!!!
Has anyone heard the news/rumor that two Chinese J-10s intercepted (purportedly locked on to) three Japanese F-2s while patrolling near the Diaoyu (Senkaku) Island? I saw an interview on the HongKong Phoenix Channel and numerous reports on Chinese websites but couldn't find it in Western Sources.