I could be wrong here, but I'd contend a stealthy strike UCAV is in many ways less complex, and because of that can, amongst other benefits to the development process, sustain a more intense testing cadence. Any naval design derived from the J-20 or J-31 is still going to be a structurally different plane that will have to undergo some additional mechanical development, and as these designs have to both fit a broader set of roles and, specifically, more kinematically demanding flight capabilities, the mechanical engineering involved will be considerably greater, even for derived designs. That's going to impose more stringent demands on the development process for a stealth naval fighter than a stealth strike UCAV, which doesn't have to cover as many mechanically intensive requirements. The lack of a human pilot also means greater tolerances for risks.
I would argue the opposite regarding UCAV being less complex tbh.
For a carrierborne strike UCAV to be viable, they need to not only demonstrate the technology to reliably take off from a carrier and to land, but also to control the UCAV aboard the carrier itself (from taxiing to after recovery)... and most importantly is developing the associated subsystems aboard the UCAV and/or aboard the ship or other aircraft, and other autonomous features, to allow the UCAV to actually conduct its mission in a reliable way that is near to what you would expect for a manned fighter... keeping in mind a key problem they will face is opfor jamming and interference against your UCAV control.
That said, I do agree that a fighter naturally has higher structural requirements and complexity compared to a UCAV -- but those structural requirements and complexity are all things that the Chinese aerospace industry have done before and have reliably gone through the paces for developing and testing.
OTOH, developing a reliable carrierborne UCAV, I think entails developing far more new subsystems and software systems where you not only have the issue of developing a system to make the UCAV reliably fly off and land and taxi around the carrier, but also to develop an entire family of shipborne and/or airborne subsystems and datalinks, as well as integrated autonomous features to allow your UCAV to be able to function as a reliable striker in the face of opposition...
Between those two options, I have far more confidence that the CAC or SAC would be able to produce a relatively mature naval stealth fighter by 2025 than a relatively mature naval strike UCAV.
We disagree on the cost of the feature I think. A larger bay might incur other penalties and compromises that are nontrivial, either in program cost, design complexity, or reduced capabilities. Making the bays bigger sounds like a trivial change, but the design decisions that go into fighter planes are tightly interdependent optimizations, where changing one variable can have nonlinear cascading effects that can result in suboptimal outcomes. One way to get around these problems for planes is to simply include a more powerful engine, but that is not yet a reliable option for China, given the state of their engine technology.
I think this may be it.
I see increasing the volume of say, the J-20 weapons bay to allow it to carry JSM or AARGM-ER sized missiles to probably be a relatively low cost thing to achieve (and even more so when considering the benefits it will entail).
Also, I think the naval derivatives of J-20 or FC-31 will be different enough from their land based counterparts in such a way where there will be cascading effects anyway.
To develop the navy's premier next generation stealth fighter without the ability to deploy stand off range weapons -- effectively denying the fighter the ability to conduct stealthy stand off land strike, anti ship missions, and SEAD/DEAD -- IMO would be a grave strategic oversight.
I think what we're learning from the JSF program is that squeezing in more multirole flexibility into one platform isn't always a better approach than acquiring the same capability through a more diversified set of complementary platforms.
I think it depends on how much multirole flexibility you seek.
I'm not suggesting they develop a V/STOL variant of J-20 or FC-31 or anything like that.
I'm literally suggesting increasing the internal volume of their weapons bay a little bit. JSF as a program obviously has very well documented issues, but I don't think its big bulbous weapons bay is a significant culprit behind them. Think how the F-35's ventral fuselage differs from the X-35 -- that's the extent of change I envision.
Of course, at the end of the day neither of us know how much more costly or performance degrading a larger weapons bay would be... but I do strongly believe that if the 5th generation carrier fighter lacks a weapons bay to carry powered stand off weapons like JSM, that it would be a very significant hindrance for its future flexibility and the overall combat capability of the future carrier strike group, at least until a stealthy strike UCAV reaches a stage of reliability and maturity.
. I wanted to post it in the thread.