What a joke they are trying to replace the Warthog with the JSF. Some of the brass in their love of hi-tech forget military history.
Twenty years ago the Air Force brass tried to replace the A-10 with the F-16. They put a 30mm gun pod on the F-16 to try to ease the Army's fears, but the real issue was the USAF wanted to move from CAS to Battlefield Air Interdiction (BAI).
BAI is about bombing bridges to bottleneck the invading Warsaw Pact tanks, and then bombing the stalled tanks, rather than waiting for them to come through and shooting them as they are engaging NATO tanks. The idea was to leave the CAS role to the Army helicopters.
Thank goodness this didn't happen. The Taliban and Al Qaeda don't have armor divisions. And CAS is everything in the current wars. Every aircraft, from an Army helicopter to a B-1 bomber is a CAS platform. The JDAM has evolved from a precision strike weapon to a utility back weapon equally suited for CAS, hence the ability to use B-52s and B-1s for CAS.
Is it too fast? Is it poorly armored?