Why is the refit based on the Type 054A sensors and systems ? Why not give this ship an AESA radar. I don't know if its possible to fit a VLS system on the Type 051B.
If I'm not mistaken, the 051B has retractable HQ-7 reloader behind the HQ-7 SAM unit. So in terms of below-deck penetration there's already space allocated to reloader and missile storage. Refitting it with VLS system is prolly not difficult.
AESA systems are quite expensive and require even more major rework on the ship (structural, power requirements, etc). The HQ-16 VLS is at least better upgrade than HQ-10.