I didn't deny the importance of the airframe altogether -- I said in comparison with sensors/networking/EW/weapons, the airframe/kinematic performance is at best a secondary if not tertiary in relevance for consideration of what differentiates a 4.5th gen aircraft from a 4th generation aircraft.
As it turned out few days ago, at least EW may have to go down in priority list, and there's at least a slight question on elaborate sensors (what good is this comprehensive set of everything, if straightforward set of larger radar, bigger stick and datalink reigns superior?)
Otherwise, assuming that fighter is up to a world standard in sensors, networking and weapons(i.e. it can fight and not get slaughtered in the first place), that starts becoming decisive is performance. Because contested air combat is positional, position is won, all else equal, by a side with better energy retention.
Which puts me back to the original question -- do you still believe J-16 is not a credible and thorough 4.5th generation aircraft?
I don't frame it as "credibility".
I frame it as distinguishing between different bases.
I.e. 4++ and 4.5 mean more or less the same in terms of electronics, and are to be considered equal. And individual platform merits are generally more important (which is why j-16>j-10 regardless of this distinction, for modern China; it's simply more useful).
But, in specific circumstances where signature and supersonic performance matter(contested/congested environments above all), I'd prefer keeping track of platform age(and original purpose).