I agree. Compared to industry leaders WS-10 is not an impressive engine. In fact it's about the same level as CFM56-5 which is very much legacy tech for the west. But it does facilitate the emergence of future, more competitive engines by giving China a solid foundation to work from, and that is its true significance. With the WS-10 out of the way, successive turbofans will have a more straightforward testing and certification process that doesn't involve incessant trial and error, paving the way for China to eventually match and surpass western engines.
Not an impressive engine at all compared to US turbofans but the WS-10 engines are exceptionally impressive in that it is one of around six engines (in service for years) in the high thrust and above category, out of dozens and dozens of engines still being used around the world. Al-31 family, WS-10 family, F110 family, Al-41 and 117 family, F119, F135.
It is no easy task to develop an F110 or Al-31 level engine. So far only China has been able to outside of Russia and USA. The UK can certainly do it but can do it is not the same as have done it already and that's not the same as have done it, modified and improved it and used it for over 10 years and produced an entire family of the engine.
F119 and F135 represent a step above. WS-15 aims to be in that class and it's getting into service. Russia's Project 30 too. These two newcomers have a long way to go to mature and iterate. All of these are pretty rare and world class. After all they are in a club of their own with no one else in Japan, Germany, UK, or France even coming close. Need and requirements blah blah sure but having done it is something impressive is it not?
Turbofans will eventually reach a design limit. There is only so far candle technology can go to produce light.
You can keep improving certain aspects but there is always a higher peak to seek out. This for 6th gen engines has become fairly well defined as variable cycle which so far only US and China have programs for that we know of. Perhaps UK has its own since they are an aviation powerhouse and maybe Russia and France too. Beyond that it's combined cycles and more exotic propulsion tech that isn't well known in the public domain.
I'd say China's turbofan tech has been surprisingly impressive given they started much later with fewer resources, and a lower knowledge base (at the start). Already China is one of three nations to have high thrust turbofan. 3rd gen materials level vs the leading edge 5th gen materials. Almost all major leading engine tech and manufacturing tech have been mastered and done, except ceramic composite blades.
Considering resources were split to also cover variable cycle engine development, TVC, combined cycle engines, scramjet/sodramjet for hypersonic vehicles, and research into other propulsion technologies, China has been surprisingly impressive with how far its come along with turbofans given how far behind it was in ... everything and how close to leading edge it is in ... everything now. In fact in sodramjet and scramjet, in the lead. Russia is claimed by certain fairly credible Chinese commentators to be a dominant player in scramjets (well keeping scramjets running in >mach 7) ... along with China which has kept what Chinese sources claim is some special form of scramjet engine running for long enough to circle the earth. India couldn't keep a rudimentary scramjet working for even 20 seconds at mach 5 which is lab level easy for even 1990s standards.