I have seen diagram where frigates are the inner ring protection for the carrier. Wouldn't you want the frigate to quad pack some shorter range missiles for that purpose.
People keep thinking of the AKJ16 as some sort of mini-VLS when it’s basically the same size as the US mk41. So there is nothing stopping China from putting a quad packed missile in them if they wanted to. With the huge number of 054A, and now 054B using this cell, it’s future is assured and continued development support will eventually add all sorts of options.
Personally, my view is that the PLAN prefer the HQ16 over any quad packable missile because of the massive performance gulf between them. Don’t get fooled by the brochure sales pitch numbers for the likes of the ESSM. Their max range figures are only achievable under ideal circumstances, and when the target of the attack is the launch ship itself.
Due to its small volume, an ESSM will only be able to engage its engines for a fraction of the time a HQ16 can manage. After fuel is exhausted, the ESSM is just gliding and loosing speed and energy all the time while the HQ16 can sustain powered flight and full performance for far longer.
This gives the HQ16 higher PK at extended ranges, as well as the ability to intercept missiles aimed at other targets the ESSM simply won’t be able to, such as high supersonics and maybe even hypersonics under some scenarios.
This in turn allows the PLAN much greater flexibility in fleet formations and deployments of the 054A within a carrier or similar strike group formation and still being able to offer effective area defence for the fleet’s principle warships and other escorts.
Simply put, frigates are restricted to operating within a small inner ring around the fleet’s principles if they pack many small missiles like the ESSM, whereas with HQ16s, the longer range and sustained speed of the missile frees up the frigate to go further from the principle while still being able to offer the same or better degree of protection to the principle, and that opens up a much bigger range of missions the frigate can undertake, and also pushed out the fleets effective air defence bubbles.
The use of different VLS could also be the PLAN’s way of answering the modern question of what the difference is between a FFG and DDG. The UCCL VLS seems to be focused towards long range SAM and offensive firepower, whereas the AKJ16 is focused on defence with HQ16s and ASROCs.
The UCCL VLS will be more likely to get a quad packable 5-5-5 missile since the ships mounting them will be DDGs and CGs, so more likely to be worthy targets of saturation attacks themselves.
The 054B also adds a decent amount of anti-saturation capabilities themselves in the form of the HQ10 launcher.