Six Type 052Cs and eight or more Type 052Ds by 2020 will be a powerful force in and of themselves.
Ultimately you will probably have a total of 18 Type 052C/D DDGs...and that will be nothing to take lightly for any nation.
When you add another eight or more Type 055 DDGs into that mix...as I said before, next to the US Navy you will have the largest single nation Destroyer force out there.
Add the probably 24 or more FFGs, and you end up with a total of 50 very modern, very capable surface combatant (not including what will probably be over 40 Type 056 vessels).
At that point the PLAN will be as large, as modern, and perhaps as capable in terms of pure weaponry and electronics (though perhaps not in terms of overall experience) as the ROKN and the JMSDF combined.
There are two big questions important to the PLAN's projected surface combatant fleet imo.
One is their build rate.
The second is what their final critical mass count of ships will end at.
Currently they are averaging 7 056s, 1-2 054As, and 2 052Ds a year. If we have no idea what kind of end game orbat the PLAN wants, then this is our best estimate for trying to project the overall count of PLAN surface combatants up to the forseeable future.
But the second question is much more important of course. A current 1-2 054A build rate means nothing if production finishes after the 24th unit in a year; so naturally we'll need to consider if the PLAN will seek to introduce a new serial production frigate class to supplement the 054As anytime soon or if they'll only build a new frigate class in a few decades' time once the 054As need to be replaced.
But by 2020 I do expect all 24 054As to be commissioned, with the 18 052C/Ds commissioned, and 1 or 2 055s as well.
I have no idea where 056 production will end up. There are rumours we might see a total count of over 60 056s once things are said and done. Certainly by 2020 I expect several dozen 056s to be in service, which isn't very far off considering 19 056s are already commissioned even today.
At that time frame, the ROKN will have perhaps 6 Se Jong class. The JMSDF will have four Atago and four Kongo class, plus another five Akizukis. Together, they will have about 20 heavy destroyers and the PLAN at that point will have 26. (Actually more if you include the Type 052Bs the Type 052, Type 051C, and the Sovs...but I am really talking their principal DDGs here).
I've been waiting for ROKN and JMSDF to announce additional aegis ships, however I haven't seen any firm commitment to new ships as of yet. Maybe I'm just not looking in the right places.
I'm aware ROKN have an option for 3 additional Sejongs, however DSME seems to be offering an 8000 ton 64 VLS KDDX option as well?
I also expect JMSDF to have more aegis ships lined up to supplement their current six, and there was noise a while ago about two new Atagos joining the fleet 2020-2021, but not much since that.
Of course then the elephant in the room will still be the US Navy who will have at or over 90 CGs and DDGs combined in that time frame.
Anyway you cut it though...the Type 052C/D and Type 055 Combo is going to be a very powerful and capable combination for the PLAN.
The thing to watch, imo, is how much bigger the PLAN's surface combatants numbers will continue to grow.
I say this, because chances are the USN won't dramatically increase their CG/DDG numbers, and new ships built will offer an evolutionary increase in capability versus their predecessors (for instance Burke IIIs offering improved evolutionary capabilities versus say, any Ticos that they replace). OTOH, the PLAN will be replacing old 051 luda destroyers with 052Ds, which is a much more revolutionary improvement in capability, relatively speaking, and we also don't know whether the PLAN are planning to increase their absolute number of surface combatants as well.
That said, the USN will definitely maintain the world's largest fleet of large destroyers/cruisers for decades to come.