BTW, I am not talking about China using fighters for anti-shipping role against India. Its to be used against US and the west pac. Having H6 to carry YJ-12 is certainly good. But I feel, current YJ-91 is just too short range and thus fighter level strike air crafts like J-16 currently have a capability gap.
Yes YJ-91 isn't a good platform by today's measure. It's only updated by its modernised electronics and that's assuming this is the case.
YJ-12 is a fair bit more modern but uses the exact same concept as Moskit to Kh-31 just with much more modern and sophisticated electronic components. They're okay for their roles and what they are. missiles you can build and stockpile quickly, easily and in the tens of thousands over the decades. They're modernised by updating their electronics, software and whatnot and they perform supersonic cruise and mach 3+ terminal speeds. That's good enough for what they need to be. Certainly all these missiles are arguably a class above older subsonic non-stealthy cruise missiles fielded around the world in the 20th century and continue to be. After all Neptune was able to hit a Russian cruiser (if we're to believe that it was the Neptune). Perhaps what made that possible behind the scenes is EW and ISR related rather than the platform itself.
China just moved on with these types of ordinance because it is facing the US not India. It needs to be that much better than playing boring old supersonic missiles with India. It's why it has developed and fielded various types of hypersonic missiles that can be launched from ship, space, air, and land. What's more strategically and tactically important is all the other stuff - ISR, EW, comms, network resilience and so on. In these fields, India is barely a bug at the moment and it appears their political structure actually isn't better at getting shit sorted than China's. In fact, if anyone is honest, it is quite a lot worse and China isn't even that great at it despite what China fearmongering westerners often claim.
China should develop some more stealthy air to ground ordinance than the few it's shown in shows that aren't in service as far as we know and the one that is potentially in service shown with the J-16 years ago. Better if these can be supersonic but it's going to be less stealthy than it would otherwise. In the meantime, YJ-91 is 90% as good for its role and it's been made for a long time. Just keep upgrading rocket motor, fuel, software, and electronics as those tech improve over time. It's mechanically not a bad platform.