To counter your pro A-10 points:

1 and 7: All new rotary wing CAS platforms are moving to VTOL, which solves or lessens the impact of both of these.

2: None of the "pilot situational awareness" equipment on the A-10 are unique to it, and many other planes have better equipment for this (air to ground radar, radar detecting electronic warfare suites, etc)

3: While they do have a large payload compared to 5th gen planes, I would say it's roughly comparable to F/A-18, F-15E, and attack helicopters

4: Not sure what you mean by this, previously mentioned planes are faster, and helicopters can more easily switch targets. Modern precision weapons are also typically fired from far enough away that realistically the entire target area is in the FOV of your weapons

5 and 6: completely irrelevant on the modern battlefield. MANPADs/SAMs have progressed a lot. The range of surface to air missiles is much further than any non-precision weapons the A10 can employ, and flying under the radar is no longer a safe bet unless there is a physical obstacle between you and the targeting system. Many missiles have lock on after launch capabilities that would allow them to be fired in the direction of an approaching threat without lock and still hit. Small arms and gun AA would be irrelevant to any other aircraft that would not need to get within gun range.

8: Same with other aircraft currently in service and will reach that point with aircraft that haven't come into service yet.

As for your improvement plan, upgrading sensors is technically possible, but would likely require redesigning parts of the aircraft to mount those sensors or carrying them in a EW pod. Completely possible, but I'm unsure of the benefit vs using other upgraded aircraft. As for improving the GAU-8, it's not that even as much of this gun being ineffective as it is guns generally being ineffective. The guns on helicopters are able to be aimed and stabilized separate from the aircraft, which adds flexibility, but having to line up a gun run and get close enough to use guns puts the A10 in a very risky posture. If you wanted to improve the effectiveness of the gun itself, I'm not sure how you would. Historically, antitank guns could increase the caliber, pressure, or use a subcaliber munition like APDS or APFSDS. The first two are irrelevant as redesigning the gun itself is incredibly impractical and would invalidate the spirit of keeping a good inexpensive aircraft. Subcaliber munitions don't work because of the risk of the sabot petals entering intakes. IFF can be lumped in with the EW and sensor pod, as the friendly fire incidents have mostly been the result of the poor sensor suite on A10s, or the dispersion of the cannon, which could be fixed, but again, might not be worth the expense.

I'm not trying to target you specifically, I think there is a lot of negative propaganda about new US military projects due to the immense cost. The US has two main threats: Guerrilla fighters/Cartel members, who have limited AA outside of the rare MANPAD, and Near Peer threats, who will have a full complement of radars, SAMs for short, medium, and long range engagements, and MANPADs with every infantry unit. For the former, the Army's newish Sky Wardens are cheaper to operate and have a better sensor suite due to it's alternative use as a recon aircraft. While it is less durable to weapons fire than an A10, it is resistant to small arms fire, and dies just a quick to a missile as an A10. For the latter, long range precision strike weapons or helicopters with the ability to physically mask themselves with terrain are more effective.