J-11D, air-superiority Flanker.
Would have featured AESA radar, more hardpoints, revised structure, new engine, etc.
Ultimately canceled as J-20 program was successful, and around the same cost to produce.
Some technology developed ended up in the J-15T revealed in Zhuhai this year.
This one is pretty good! But considering the delay in the appearance of the J-11B, which was supposed to appear with the F-15C, I think it is obviously too difficult to wait until this aircraft.