I was told by someone inside, the J7G will stop be produced once export #'s are filled, But the source is from another company whichin the First Aero Group Companies, so he may be wrong. A lots other countries are looking at JF17 or even J10 to buy, not J7G anymore, So I think the export market for this jet is drying out fast. As for JF17, I am sure the PLAAF will field some into its services since all these changes on this jet have made it that much better. But overall, I think the JF17 run counter to the way PLAAF should ( and is ) going in the future. crobato and other knows a lot more than me on how good or bad a jet can be, but I think the biggest failling for the JF17 is her size, if you cram in too many capabilities into this jet, range suffers( too much added weight) and it will become too expensive to OP. Then the better buy will be J10. But if JF17 is built cheap and simple, then its capabilities will be too limited to be much of use in modern airwars. Crobato and others may have a different point of view and I am listening.
As for the H6 production, By the look of the new engine intake and all the needed changes inside for it to carry 6 CM and flight control changes, I would think it will be built new, not refitable to the older airframes, so, XAC will be very busy for longtime to come.
The airframe "size" of the JF-17 is not as limited as you think. The plane is actually slightly longer than an F-16. Weight is no longer related to size. The F-35 is only a foot longer than the JF-17 and weighs six tons more.
Space is not the issue, as the engine power. A much more powerful plane can carry more weight and suffers less performance penalties. FC-1's relatively low power means just that. Look at the Gripen, the next version would make it weigh over 7,000kg empty, and so needed an upgrade of the engine to the GE F414 (used by the Super Hornet).
Fortunately Klimov/MiG does have an upgrade plan for the RD-33, which can extend all the way up to 10,000kg. Then of course, there is a Chinese alternative as well. Avionics are also getting lighter as time goes by due to electronics miniturization.
You already said correctly that the JF-17 is running counter to PLAAF future trends, which is very much like with the rest of the world---growing bigger and heavier. I think that's the greatest barrier for the JF-17's acceptance into the PLAAF. But this trend is going to run into a brickwall sooner or later. Technology and size cannot replace numbers and availability fully. 100 big fighters are not going to do the job of three hundred small fighters without pilots being exhausted and planes physically worn out to the ground. Fewer planes means less planes to occupy the battlespace and less planes to be available for missions of opportunity. When attrited, having smaller numbers mean a greater impact to your force. Numbers will always count no matter what.
In my view, a plane like the JF-17 can be served greatly with networking, like the Gripen. Numbers, especially when organized properly, can be very effective. This is not to say bigger planes don't have their place, they do. Large jets like Flankers can serve as eyes and sensors for smaller planes, and these smaller planes act as tactical backups to the bigger jets.
Its not necessary that you have to make a small jet do everything, and so have everything crammed into a little airframe. Small jets do better when it comes to specialization, while with bigger jets, you're looking more into generalization or jack of all trades. With specialization, you only put what is necessary for the design role into the aircraft. Having said that, the FC-1 is still clearly intended as multirole, but its not like a wide area defense interceptor and air superiority platform or major strike bomber. The fact its replacing A-5 units in the PAF, indicates a tactical support role. The fact that the PLAAF has other designs that can undertake other sordid tasks more suited for heavy fighters, puts less weight on its small fighter requirements.
