Just circling back to this point, specifically the underlined part...
I think I would agree with you that J-20 is itself not "long legged," in the modern context and in the theatre it is expected to operate in, because the future of air power in APAC will likely be one where air superiority fighters have increasingly greater range and persistence. In that context, J-20's internal fuel range and endurance is probably average.
However, what that means is that F-22's internal fuel would comparatively have to be called "short legged" in the same sort of context.
But otherwise, even with a large or larger internal fuel capacity for J-20, it would still make sense to have a non-stealthy "ferry" configuration with more internal fuel tanks for certain mission profiles or deployments where it may be useful.
As far as designing and testing the aircraft for four EFTs go, I think the treasure and time spent on that is fairly small compared to what the rest of the aircraft's design and development would be, yet spending that small amount of time and money opens up substantial flexibility. Just because the F-22 only carries two EFTs rather than four doesn't necessarily mean it is not worth doing in other aircraft. If anything I wonder if the USAF might be kicking themselves a little for not spending the cash to allow the Raptor to carry four EFTs, in hindsight.
