Well, to paraphrase Equation, "it's all about the program".
It's not about how effective the Sukhoi airframe is, but coming up with their own design. Even if their first attempt is worse than the Sukhoi, that's ok. Just keep improving and keep coming up with new designs. In that sense, I applaud their efforts on the J-31. It's not successful yet, but at least they are trying. But they need to stop modifying Sukhoi variations.
It's a mindset. They need to come out of the Sukhoi box to be truly independent. To do that, they need to stop copying Sukhoi.
I questioned the J-11D program from the beginning, China has done a very credible job re-placating the amazing Sukhoi, and SAC has been aptly rewarded. Blitzo is to be commended for two very well thought and informative posts, getting the Sino Defense post of the Day award..... so whether or not SAC continues to build Flanker upgrades, or China buys several SU-35s to step into that role is almost irrelevant. If Russia is able to build an acceptable Flanker, which is an airframe that benefits very greatly by having OVT, then SAC is freed up to do other work??
In the US, even though LockMart officially builds the F-35, Boeing and NorthRupp Grumman are building significant assemblies, NorthRupp is building the very precise and strong center fuse with Robotic welding in order to bring up production rate. At this stage of the game, why not allow Chengdu a little help in order to move this project along.
Finally I would remind each of you, that a Flanker, is a Flanker, is a Flanker, no need to re-invent the wheel here gents?? Chinas builds some very high quality Flankers, but none currently offer OVT, which the SU-35 does. Its quite likely that the SU-35 which I have been especially critical of, and see no reason for China to import, is an outstanding option to get more aircraft on patrol in the SCS in a hurry.
More importantly, it is far more critical to ramp up J-20 production as the First F-35s are already in Japan with their F-22 sisters?? so its NOT just about the program, it is about the "platform" that is capable of defending and hopefully defeating the emerging threat?? SU-35 in combination with the J-20 offer the most logical extenstion of that idea at present, they just need 30 times the J-20s they now have, and theres only one way to ramp that number up.
Think about it, SAC has a very fine capability of "replicating" existing equipment,,, no one here would dare tell me CHENGDU is able to meet that need!