One of the reasons the A-10 was and is so successful, is that it was designed with the help of the greatest ground attack pilot in history: Hans Ulrich Rudel, famed as the "Stuka Pilot". The most decorated German serviceman of the second world war, he was credited with destroying no less than 519 Soviet tanks, a Russian battleship, and they just plain lost count of the gun emplacements, vehicles, barges, and various whatnot that he blew up in 2530 operational sorties.
Rudel was engaged as a special consultant by Fairchild/Republic when the A-10 was being designed in 1972 against the expected Soviet offensive through Germany. And who knew more about stopping Russian tanks than Rudel? His wartime memoirs were required reading for the design team.
Funny how it always comes back to basics.
Bob C