The Mig-21 example was given to reflect how even very growth limited designs such as mig-21 can still show remarkable growth possibilities to re-enforce my theory that some older jets which are still far newer and more complex than "AK-47 of the skies" and with far greater growth possibilities could still do the job perfectly fine.
Don't forget that F-35 itself is not a big plane either, it's F-16 sized and due to the stealthy shape, it's nose does not provide much room either still enough for the AN/APG-81 though...
Sure, no external pods needed but for any meaningful load, external hard points needed very much....which means less stealth, more drag, etc. I highly doubt EOADS couldn't be integrated on F-22 or even some older machines either.
The real question is, what kind of airspace denied not only for A-10's and AV-8's but also S-Hornets, Falcons and Eagles would be appropriate for the F-35?
It's stealth is already downgraded from very low observability to just low observability, goodbye brother Raptor, hello brother Super Hornet, and on top of that it's internal loadout options are as I said quite low(4!) but hanging external ones means even less stealth.
Can such a plane really be appropriate to be sent into airspace with multi-layered air defense and strong air opposition? I mean if for example picking off radars from like 50 miles away with HARMS with awacs supported Eagle escort is too risky how to hell is F-35 suppose to go there and drop say JDAMS on S-300 sam sites and fight Su-35's or God knows what?
What? He will fire JASSM's from far away? Sure that's cool, but the list of JASSM platforms is quite long, B-1/2/52, F-15/16/18...
On the other hand, maybe it will not go into fight against multi-layered air defense supported with excellent and well equipped enemy air-force, but what will it do then? Drop JDAM's on some camel-f**ers?
Heck you can do that with T-6 Texan II, but then Lockheed wouldn't collect several hundreds of bilions of dollars from the defense budjet(s)
Now sure I'm not an engineer, military strategist or anything like that, just a mere aircraft enthusiast so ofcourse I have apsolutely no idea how will it turn out in the end, but from the info that comes out, I really see nothing spectacular here(except development cost), it's uber cool in looks department, electronics is like it came out from a Star Trek episode, but aerodynamics department is kinda dissapointing as are the load options under max stealth conditions which are not impressive to start with which in turn gives some raising questions on it's mission purpose...