China's GDP grew by over 15 times within the past 25 years. Assuming a military planner will procure weapons which are proportional to a nation's economic capacity No planner could have predicted China's staggering rise. This explains the PLA-navy's bizarre mix-match of weapon systems. For example, What Navy on this planet has a combination of 225 ton missile boats and 50,000 ton amphibious assault ships with EM catapults? Sometimes truth is stranger than fiction.Effectively PLAN is already a 5 tier navy, considering the 054A production has been continuing until recently. They do not need another layer between their existing surface combatants. Maybe later they would introduce an even higher layer. I see even that speculative
Anyways I think in the future as China's economy matures its navy, the surface combatant fleet, will eventually evolve into 3 tiers: frigates, destroyers, and cruisers.