The main problem for the A-10 is widely available, effective MANPADS. I'm not sure what you can do to immunize your attack aircraft from them, but I am pretty sure that the F-35 isn't the answer.
You can't. What you can do, is make attack aircraft more numerous, cheaper, and more expendable -- which almost certainly means unmanned. Manned combat aircraft are becoming dinosaurs for much the same reasons as battleships did.
Most MANPADS have warheads weighing less than 5kg, a few kg of HE is enough to cause significant damage but the A-10 was built to fly with half a wing, one engine, one rudder/elevator assembly, and a mountain of shrapnel stuck in the pilot's armored tub. MANPADS will get a mission kill on an A-10 but they aren't powerful enough to bring one down the majority of the time.
Stand-off attack with smart munitions is a different role than CAS; so this isn't so much F-35-can-do-CAS as F-35-is-sufficient-because-CAS-is-not-necessary.
EDIT: to be clear, I am characterizing the position here, not endorsing it.
It's been said before, turned out to be untrue before, and I see no reason to believe it this time. Until someone finds me some credible infantrymen who say that CAS isn't needed, I will not support putting boots on the ground without a strong CAS game.
EDIT: re: EDIT: Fair enough! Don't worry, I haven't downvoted you or anything like that. As far as that position, I feel like it is maybe not the most honest one from some folks since the F-35 has been touted by some as a platform with which to do CAS.
Stealth?
I love the old warthog, but in the days of drones, I can't see much of a use anymore.
For close air support, maybe the US wants to use fast, stealth aircraft firing missiles to spots specified with laser designators, GPS, etc.
As I recall, at times the USAF claimed that to kill tanks an F-16 with a missile was better than the A-10: Sure, the gun on the A-10 is amazing, but the A-10 flies low and slow and should be vulnerable to, say, MANPADS. The F-16 flies higher and faster, fires a missile, and then is out'a there.
Maybe the USAF wants the F-35 to be better, still: Use stealth.
Sure, maybe soon the USAF will want its missiles to kill tanks, etc. fired from drones, maybe even stealth drones.
>For close air support, maybe the US wants to use fast, stealth aircraft firing missiles to spots specified with laser designators, GPS, etc.
Yeah, the Air Force always says that, and the ground troops always demand A-10's Apaches, etc.
>As I recall, at times the USAF claimed that to kill tanks an F-16 with a missile was better than the A-10: Sure, the gun on the A-10 is amazing, but the A-10 flies low and slow and should be vulnerable to, say, MANPADS. The F-16 flies higher and faster, fires a missile, and then is out'a there.
The Air Force always claims that they have a good reason to get rid of the A-10.
The fart-gun while awesome, isn't the real reason troops love it so much. The ability to loiter on station for a long time and keep enemy forces down in defensive mode is. Neither fast-movers, nor helicopters can loiter as long.
>Maybe the USAF wants the F-35 to be better, still: Use stealth.
Stealth isn't a panacea, it's a buff against the enemy's radar. And, yeah, drones/unmanned are the future.
Some versions of stealh try to lower their heat signatures, e.g., hide the jet engine output from the ground by an extension of the part of the plane below the engine and mixing the jet exhaust with cool air. For the F-117, can get a little view of its engine output at
http://aviation-design.fr/images/jets/rc-jet-model-f-117/lar...
Looks like they tried to hide the exhaust heat.