I thought the Type 054 is the closest counterpart to the FREMM? Frigates are meant by the PLA to have medium air defense assets and emphasis on ASW warfare, so I don't think a common VLS is exactly in their interest.
FREMM is some good 2000 tons heavier than 054/A and is less a frigate in the traditional sense (like 054/A, OHP, la fayette) than a medium weight AAW DDG like 052C and type 45. Of course it isn't just about weight, the sensors and aster missiles aboard FREMM are a generation or a half than HQ-16 and sea eagle aboard current 054A.
How would a common VLS not be suitable for frigates? You realize they come in different lengths right? A frigate may not be expected or have the draft to be equipped with VLS scalable forLACMs but being equipped with a medium length version will allow it to fire SAMs, ASROC style weapons and future weapons developed. Once the common VLS is developed and mature, the question should be why
shouldn't they be installed upon frigates (and even older vessels or smaller corvettes)
I wonder if the tonnages in A man's chart were for standard or full displacements. Wikipedia lists 052C as 7000 tons, I think most of us expected 052D to weigh a noticeable bit more.