someone was asking about the Canadian air to mud role being gone- not so. The low level delivery has been replaced by high level delivery. In the "old" days, pilots stayed alive by going low level, under radar coverage, and being faster than the missiles fired at them. Worked well, but we lost a lot of people due to the inherent risks of low level/high speed flight. As equipment progressed, we were able to suppress enemy air defences to the point that low level radar avoidance was no longer necessary, and have dropped the capability. Air wars are now fought from high level.
Close air support is a role that is still being carried on today, but insted of roaring in low level, troops are suported by high altitude drops. The Mission hasn't changed, the Air Force still exists solely (as we all do) to support the 19 year old with muddy boots and a bloody bayonet hold the ground we helped him win.
As for airframes- the USAF got rid of the A-10 many years ago- the Reserves fly them now. They do very well when air superiority has been gained. As for the Harrier/AV8-B - no thanks. It's not as "field compatabile" as they make it out to be.
The Apache is a superb platform, but needs maintenance regularly. Spare parts and a clean maintenance facility will keep it airborne, but you need both, along with down time, to maintain a long push.
In my opinion, Army helo's need simplicity and durability. The Kiowa and Single Huey were great examples of what the Army really needs- simple, robust aircraft that are easy to fly and maintain, and have enough capability to do the job.
Cheers-Garry