Sounds like you are referring to an 15-19,000 tonnes Cruiser with 140-180 VLS cells. But building such large ships means:What I see is larger combatants are becoming the trend. Frigates are now the size of cruisers in WW2, destroyers are becoming cruiser sized. After some years, the 055 may not look so big after all, and there maybe bigger surface combatants as part of this trend.
I don't see building more 056 like ships in the future, unless the PLAN goes to the Russian route of building corvettes with a few large anti ship missiles.
Setting the bar is like working on a sliding bar scale. You have to know where exactly you want to slide the bar in the middle between the two extreme ends.
I still see the need for a frigate, which can be defined as the smaller size that you can make and cost, and still be regarded as fully ocean going, blue water, capable of carrier escort, is capable of ASW, ASuW and AAW operations. It may not be the best in AAW operations versus a destroyer or a dedicated AAW vessel, but it should still have a respectable and potent capability of it, even if diminished compared to larger ships.
This is followed by an upper tier where you can have dedicated AAW ships, or ships that can contain enough VLS for everything else.
Naval history lesson has shown you do not neglect the importance of the Escort. They do most of the fighting and dying like they did in WW2. Of course, our idea of the Escort keeps going bigger and bigger, and in fact the 055 can be considered an escort. If mega ship trends continue, we will see larger and larger surface combatants. But not necessarily arsenal ships.
1- It takes longer to build
2- Not many will be build (and if they build them, it means something else will not be build in more greater numbers; maybe a 052D/E or a 055A/B. Unless budget can support the expansion of both classes of ships.)
3- The cost/risk for this ship will be high since they will be high value target for the enemy. Will they need an escort of their own or will they dedicate 90% of VLS cells for SAMs. Then what will be the point of having such a large ship, unless to lead an SAG with 054s, 052s, and 055s. This will help allocate some VLS cells for offensive strike missions since AAW roles will be covered by others.
4- Purpose of having a large Cruiser--not serving as an escort to Carrier--roaming in coastal/regional waters (1st and 2nd Island chains) when that role can be fulfilled by 054 variants, 052 variants, & 055 variants. Plus these waters will be littered with unfriendly neighbors, all having land-based anti ship missiles. So again majority of VLS for SAMs and less for strikes on land or anti-ship missiles.
5-Might be a great platform for ASW roles but not a huge difference from 055 probably.
In the end I do believe PLAN will build a cruiser but not in huge numbers. Maybe half a dozen or a dozen to serve in SAG; Point #3. Dedicating more VLS for other things than AAW or simply to bring more VLS to the fight.