Comparing with other navies the Chinese may want to keep the three tier structure simply because of cost concerns.
One of the main issues China has is lack of anti-submarine warfare capabilities. A new frigate class which is dedicated to the role would go a long way in addressing this.
I think PLAN's organic ASW capabilities among blue water capable surface combatants has already been greatly remedied with the 054A and 052D classes, with the latter half of the 054A's production run having the VDS+TAS combination and all 052Ds having VDS+TAS. Similarly, 055 has the same VDS+TAS set up. We know 054A can fire the vertically launched Yu-8 ASROC type weapon, and I wouldn't be surprised if the 052D and 055 are able to fire a similar type of weapon from their VLS in due time if not already.
Older 052Cs and the first half of 054A production run also have a TAS as well (but no VDS).
So in terms of organic ASW capabilities on blue water surface combatants I think the PLAN has probably enjoyed a massive advancement compared to the first half of the decade.
Of course, what PLAN surface combatants do need going forwards is high availability of a capable medium weight ASW helicopter which a Z-20 derivative is expected to fulfill.
That said I also do think the PLAN needs a successor frigate class to the 054A; a ship that is maybe up to 1000 tons heavier than the 054A's 4000 tons. The 054A is a very decent ship for AAW and ASW, but it could definitely be better as well, and I expect 054B's mission to be a combination of ASW and AAW (predominantly medium range), and to take advantage of various new advancements like the new universal VLS to enable firing of newer contemporary weapons, new air and underwater sensors, IEPS, possibly twin helicopter hangars, and so on.
(And of course for ASW we can't ignore many 056As they have are also equipped with VDS+TAS as well as the ability to fire the air breathing ASW ASROC weapon from slant launchers used for YJ-83s, but 056As obviously are not blue water capable).
Literrally every navies have been based on a "three tier structure". There's nothing special from China about this topic.
Not all navies have a three tier surface combatant structure. Remember we're talking about the PLAN's blue water capable surface combatants here, that will soon be characterized by 055 weight class, 052D weight class, and 054A weight class.
The Royal Navy has a two tier structure with Type 45s and Type 23s (latter to be replaced by Type 26 mostly and a number of slightly smaller Type 31s), the JMSDF has their big aegis ships (Kongo, Atago, Maya soon) as well as a number of medium weight destroyers in the form of Asahi, Akizuki and their predecessors.
The USN's surface combatant force is overwhelmingly made up of Ticos and Burkes with a number of LCS in service at present as well and the three Zumwalts either in service or due to be soon, but the bulk of USN surface combatant tonnage is from Ticos and Burkes. Furthermore, Ticos and Burkes are of very close displacement to each other with IIA Burkes displacing only a couple of hundred tons less than a Tico.
So I wouldn't say there are too many navies that adopt a three tier blue water capable surface combatant structure like the PLAN does.