Everyone is kind of dancing all over the subject here.
The reason there are different platforms is that they have different missions. First of all you can eliminate the UH-60 and VS-22. Those airframes primarily deliver troops and cargo. The door gunners on the UH-60 and the forward firing guns/door gunner on the VS-22 are meant to suppress enemy fire on an LZ.
I have personally seen the KW do a much better job in the direct support role in an urban environment. It's smaller airframe and rotor diameter allowed it to get much lower and thus stay hidden easier than the AH-64. We used it to call for and adjust indirect fires also.
Now in the outer ring of an urban environment, the AH-64 was better. For instance if a Commander knew that a reinforcing element would be coming from outside an urban area into a fight, the AH-64 could easily destroy them as they came into the AO.
In an environment that has a very low level of enemy AD, the AC-130 is hard to beat. The ability to fire 40mm and 105mm within 100 meters of friendlies (due to their ability to actually SEE the friendly forces) is great. Observed AC-130 fire on one building (a barracks) with 105mm and leave another structure 75 meters away almost untouched.
In mountainous or desert terrain, the A-10's ability to carry so much ordnance makes, coupled with its armor makes it the best option.
The F-22 is an air superiority fighter. If we have to use it to conduct CAS then, we are in trouble.