The Type 055 propulsion is supposed to be changed to an IEPS drive on later batches. There might also be improvements in weapons and electronics. China recently imported the S-400. They have done a lot of work on radar systems so they have expertise in that. If they got the improved missile designs from the S-400 and combine that with their own radar systems that could provide a significant upgrade in air-to-air range. Also, allegedly, the Chinese cloned the AK-130 dual barrel 130mm Soviet naval cannon. Supposedly it was not used because they found the increase in fire rate not that important and it is kinda of a heavy system to put on a destroyer like the Type 052D. It also did not support advanced guided ammunitions. But on such a large ship like Type 055 they could easily mount a bigger gun if they wanted to. The AK-130 was used in the Sovremenny-class destroyers and it is capable of supporting amphibious assaults with a barrage of ground pounding fire. I think railguns still need improvement before they can be used in naval applications. Laser weapons might make sense to blind incoming IR/TV guided missiles, aircraft, or drones. This is all in the realm of guesswork though.