One interesting thing that happened to keep the A-10 in business was their strong interaction with ground tactics. When the A-10 became vulnerable to all aspect heat seeking missiles, ground tactics changed: NATO antitank units were trained to preferentially target antiaircraft assets. They were perhaps 4 out of 30 of armored vehicles, and after taking them out, a Soviet armored penetration would be permitted into the NATO rear areas, and A-10s would chop them up, fast if they were using roads, more slowly if they went cross country. The A-10 remained survivable in the more sanitized environment of NATO battle areas behind the Forward Edge of the Battle Area.
As George Patton Jr. said, when enemy tanks move on the roads, the P-47 was their worst enemy. If they got off the roads, the US tank-infantry-tank destroyer-artillery team could concentrate against them faster than the German armored forces could penetrate.
The A-10 needs a somehow friendly airspace. Any Soviet fighter aircraft would have sufficient for that. But slow and low flying aircraft are hard to detect. The German anti tank helicopter was an unprotected BO 105. http://www.youtube.com/watch?v=lXNCZlQcvGw
The problem for both would be modern infrared TV-guided missiles like http://en.wikipedia.org/wiki/IRIS-T. Don’t miss to see the video of seeker head. This missile doesn’t follows the greatest heat source it follows the shape. Computer power is sufficient today to do that.
Back to the topic. F-35 will have the same problems with such missiles. Another problem for “stealth” aircraft like F-35 is radar like used on German frigates: http://en.wikipedia.org/wiki/SMART-L
According to antenna dimension the wave length is longer. Far longer than official data.