On upper part we're in agreement. My argument is that in coming ~decade displacing 4.5 with 5-6 below certain threshold will be against ongoing combat experience, and, speaking very bluntly, risky in key PLA contingencies (i am rather firmly of opinion that, should things come to that, we'd see more than few dissapointing news due to bluefor shaheds coming, say, from the island).
Here specifically, i'd like to contest.
J-20/J-35A has 4 external points, even if they are heavy duty ones; J-35 may have 6(still 4 heavy), but this is moot. None of those have immediate rocket integration. Only rare J-20S has second pilot for more complex missions.
In almost all cases, 5th generation fighters are incompatible with external jamming pods, providing 360 protection, and those don't take heavy stations.
Lol if you are focused about "rocket integration" to be able to shoot down Shahed pattern one way drones, I have good news for you -- the PLA does not have a APKWS equivalent in service currently at all.
No PLA 4.5th gen aircraft has such a weapon, so technically 4.5th and 5th gen aircraft are operating with the same limitations in that regard.
Furthermore, once the PLA does have a APKWS equivalent or something like that, those weapons can be loaded onto J-20/A/S and J-35/As external stations in multiracks as well (e.g.: we've seen tripacks of 7 tube APKWS pods on aircraft like F-15Es; that is also perfectly feasible for the likes of 5th gens).
As for jamming pods -- 5th generation aircraft have much more integrated EW systems of their own; the whole point is that they do not require self defense jamming pods. If you're talking about larger EW pods like those that J-16D carry or larger standoff pods that sometimes we see JH-7/A or Flankers carry, technically that is something they can integrate onto 5th gens as well if they really wanted to.
I'm not sure what a second pilot is important for -- if anything, the 5th gen aircraft should have greater automation, so I wouldn't be surprised if a 5th gen aircraft has comparable if not superior situational awareness than a two seater 4.5th gen (though that is dependent on software upgrades for the latter)
J-16 has 7 heavy duty stations (12 overall); that's two 5th gens worth of heavy suspension points per plane(x3 overall), and has rockets right now. Note that it appears 6th gens are absolutely smooth, and themselves probably won't be able to do rocket mission at all.
If we are comparing like for like, and accepting these aircraft will need a BVR capability for such a strike mission, then that is 4 PL-15s or 6 PL-16s, which will take up 4 or 6 of those heavy duty J-16 stations, leaving only three heavy duty stations for a J-16.
For a J-20/A/S or a J-35/A, those 4 PL-15s or 6 PL-16s can be carried in the IWB, while it still has four heavy stations for external payloads.
Or alternatively one can give J-20A/S or J-35/A each two 500kg class weapons internally and two BVRAAMs internally, and to give the same load to a J-16 will still require those two 500kg class weapons and two BVRAAMs to go on heavy duty stations.
Either way, the J-16 doesn't particularly come out ahead. At best it is non-inferior to the 5th gens.
Even smaller J-10 family can bring more or less same oversized munitions to the theater(likely 1-2, but still), once again with already available integration of rockets.
As I mentioned, no such rocket systems exist for the PLA, and if/when they are developed, there is nothing stopping them from being equipped on a 5th generation aircraft's external stations either.
Just face it -- there is absolutely nothing that a 4.5th gen fighter can do better than a 5th gen. Even as a bomb truck, the 4.5th gen fighters are at best "comparable" in physical capacity to a 5th gen, and arguably worst (especially if one compares a J-10C).
The only leg you have to stand on is "they may not integrate XYZ external payload on a 5th gen aircraft" -- but we both know that's rubbish and is entirely dependent on the existing fleet breakdown of 4.5th and 5th gen numbers. As 5th gen fleet size increases and 4th gen aircraft are withdrawn and 4.5th gen aircraft start to face the reality of being muscled out, it will be a very viable task to integrate the variety of external payloads to 5th gen types.
There is literally nothing to lose from going to 5th gens from 4.5th gens, if we accept that they're going to be producing those 5th gens at scale as described in prior pages.
PL-15 goes to external stations, as do self protection pods (chinese ones don't go to the edge stations like ru ones, which is unfortunate, but as is). With that, it's still all heavy duty pods, full flanker range and self escort.
The question isn't procurement(designed 4th gen force levels are there), the question is rushed retirement which appears to be highly undesirable per any available combat experience.
No, the issue isn't "rushed retirement" -- it's about how to optimize the fleet when a bunch of new 5th gen aircraft are going to be produced over the next decade, and if they do not greatly expand the size of the fleet?
If one accepts the above priors, then you have only two options as follows (and I'm only being partly facetious here, and partly serious):
1)
immediately mothball/preserve all of the new build 5th gen aircraft the moment they come off the production line, in favour of keeping the old 4.5th gen aircraft, and then only introduce the new mothballed/preserved 5th gens as the old 4.5th gens reach the end of their airframe life.
2)
mothball/preserve and early retire the 4.5th gen aircraft, and replace them with new build 5th gen aircraft.
