Oh my.
I've read quite a few accounts about the F-35's wonder electronics providing an entirely new capability and synergistically providing increased capability/lethality to legacy platforms.
As have we all. It's called "marketing".
In other words, there appears to be more to a 5th gen aircraft structure than just stealth, with many sensors and systems apparently needing to be integrated into the airframe and not just scabbed on.
This is true to a point, but misleading. At a certain target level of RCS it is necessary to make all apertures conformal or semi-conformal and ensure that their "windows" or radomes are stealth-compliant. There is no other benefit from such things being "not just scabbed on" - it's expensive, heavy and makes it difficult to add or upgrade capabilities.
And regarding the F-16 Block 60+/F-16V which is currently available to many Air Forces, many of those Air Forces are choosing the F-35 instead. I'm reasonably confident there is a very good reason for that, and that reason is not the oft repeated claim that LM lies thru its teeth and the various national procurement authorities are just too naive to see it.
The reason (as stated on this thread a few times), in the case of the partner nations, is that they signed on (in 2001-02) for an airplane that was much cheaper to buy and to operate, several years earlier and 2700 pounds lighter, when there appeared to be no organized alternative at all, and that (except for Denmark) none has formally evaluated any alternatives since.
It can therefore be stated as fact that they don't know what the alternatives can do, in full detail, because no competitor will provide a classified-level brief if they have no chance of a sale.
However, there's also a well documented history of statements by LockMart, JSFPO bosses and paid consultants that can be kindly described as optimistic.