I suspect you don't have the military background I possess.
Firstly, the AH-64 and OH-58 are primarily Army platforms, who use almost entirely rotary-winged aircraft. The Apache is a wonderful system -- the most badass thing in the air. It has a huge armament of 4 winglet pods (16x hellfires, or 76x FFARs or a combination thereof, plus a 30mm chain gun). But it doesn't have the ceiling of the A-10, nor does it have the range. The Kiowa doesn't have anywhere near the armament of the Apache, being a smaller, lighter aircraft -- it can only maintain 1 small FFAR tube and a .50 cal, or a two of one and none of the other.
The AC-130 is a massive bird. Puff the Magic Dragon, we called it colloquially. Fantastic engineering. But it is HUGE! It is designed to linger over an area, like a village or town, and obliterate everything in the area. 105mm howitzer, 40mm and 20mm rotary cannons. This is used when you need to destroy an insane amount of bad guys and boost morale into infinity.
The MQ-9/Predator/Reaper is nice, but it doesn't have the same capabilities of any of the above craft. Safer in that you don't have pilots put into danger. But it has less armament capability than the A-10 or the AH-64, less agility than the OH-58, and nowhere near the firepower of the AC-130.
So no, there are not "lots of things that are far better at the A10s limited role". You are ignorant. Go back to your Call of Duty.