64 VLS may be relatively few for a destroyer of this displacement...
Not sure where this idea comes from. 052D is a relatively "dense" combatant compared to its peers around the world. Ships of similar size include Spain's
Alvaro de Bazan frigates and their Australian
Hobart-class derivatives, Japan's
Akizuki and
Asahi-class destroyers, the Franco-Italian
Horizon-class destroyers, Italian FREMM frigates and their American
Constellation-class cousins, and India's
Nilgiri-class frigates and
Visakhapatnam-class destroyers. 052D is more heavily armed than all of those combatants, in most cases significantly so, and that implies trade-offs have been made elsewhere, likely to some combination of range and endurance, crew accommodations and facilities, survivability and quieting, and future growth margins. The only modern, similarly-sized combatants that are
more dense than 052D are Turkey's upcoming TF-2000 destroyers, which undoubtedly embrace similar trade-offs.
One implication of this is that it is entirely possible to imagine a future PLAN medium destroyer, one that is only modestly larger than 052D, that retains the same basic VLS configuration (or adds only 8-16 cells), with the bulk of displacement growth relative to 052D being addressed to other areas in line with PLAN's evolving strategic requirements.
Further 052D has 24 cell HHQ-10 which Burke needs to use VLS for. Granted that would be quad pack missiles but it means 052D is more like 70 VLS.
I think there is some confusion here. HHQ-10 is similar in size, role and launcher configuration to USN's RIM-116 Rolling Airframe Missile (RAM). The quad-pack VLS missiles that you refer to are the significantly larger Evolved Sea Sparrow Missiles (ESSM). An ESSM weighs 280kg against RAM's 74kg, with corresponding implications for their respective performance envelopes. RAM has historically been deployed on USN's non-AAW ships, but absent from Burkes and Ticos owing to their combination of Phalanx CIWS and ESSM. In recent years, 21-cell RAM and 11-cell SeaRAM launchers have begun to be rolled out across the Burke inventory to replace Phalanx, while there is still no evidence that PLAN has yet deployed a mid-range quad-pack missile comparable to ESSM.