Well in effect the Jiangweis and Jiankais (054/A) are or at least should be the Jianghu replacements. I'm not exactly sure how it is toughted in PLAN, but I would expect that when the 054A will enter service in larger quantives (rumousr speaks 2+ hulls already laid down so I hope that it will finally be the next new mass produced chinese major combatant) the Jianghu's number will decrease rapidly. Not by one-to-one, there really isen't big need for that, but that about 6-8 054A will replace all the existing Jianghus. Or that at least is how it should be done.
So by principle there is no need to replace the Jianghu's as such, but still between the coastal force and the larger warship there should be some vessel roughly the size of 1000 tons. It should be toughted more as replacement of the Hainan and it's subvariants, as they are not by any standarts fit for modern naval warfare.
Before I give my suggestion, few things to be clarified:
OPV and corvette/light frigate are two entirely different things. A corvette is a warship assigned to the navy and OPV is a patrol ship assigned to the martime security and survelance agencys what ever they might be in various countries. These ships may look like each others, but are not the same ships and it's not wise to have single ship operating in both duties. They may be build using the same common hull type (as will it be in my suggestion) but not that one particular ship is acting as both.
Alright. My suggestion.
We need ship with large enough hull to field all the neccecerical equipment and to have good endurance which however doesen't mean bluewater operations. The term Bluewater is used as to descripe some naval forces ability and capability to operate far from it's homewaters, practically anywhere around the wolrd. It's not simply just the endurance of the individual ships, but the over all capability of the entire fleet (support, lads, remember support, the key in all aspects of all warfare)
So where were we? Yeas, the size. As these ships should be able to perform effecient ASW operations (which means helicopter), have surface strike ability, decent airdefence, good sensors and act/pass EW suite and the already mentioned endurance we are facing one proplem: How can you fit all these in to 1000 ton hull? Well you cannot. At least not with balanced and ungrowed hull. And to add to this multipurpose hulls are not ideal solution if you have enough money so we need to at least three different class of ships.
But as the ships are approx. the same size, it's wise to use the common hull principle. So we will have a dedicated ASW frigate, a SRK (guard ship) and a OPV. The common hull will be based on the OPV build for Thailand. Some general data about the hulls: They will be ~95 meters long and 1000-1500 ton displacement. Propulsion will be 2 diesels.
The ASW frigate will be roughly analog to the Thailands ships. It has one 76mm gun in the bow and 8 YJ83 (and in this scenario we pretend that the CY-2 exists so some of the missile tubes will have it onboard) SSMs. The main difference is in the helicopter hanger. Unlike the Thailands ship, there will be a telescopic hangar and the rest of the space between the hangar and the funnel will be the main Air defence unit. Now as we paly along with the CY-2, we will also pretend that the land Based LD-2000 with the TY-90 along side the type 730 CIWS is adoptable for naval use also and thus we have somewhat Kahstan like powerfull anti-missile-missile and CIWS hyprid. The telescopic hangar accommodates one Z-9 size helicopter. A new small size LF VDS is fitted along new bow mounted LF sonar.
The SRK variant is basicly the same as the ASW version, only that the large funnel is not fitted (diesel powered ships are not tied to the funnels as steam and gas operated ships). As so total of 16 SSMs can be fitted. The SRK has only the bow mounted sonar.
The OPV variant is as the Thailands ships. The Helicopter hangar is fixed and there is no CIWS. Two single barreled 37mm AA or new dual 14.5 mm MGs will be fitted alongside the hangar. SSMs are intended but not carried. The sonar is hull mounted and not fit for active search and attack.
Now I will post a linedrawing of this ship as soon as I'm getting there (I'm actually drawing all the chinese major surface ships) so it may take a while...