FYI, RUb includes all the latest work that has been done on AirPower, and this has been the case since the very beginning
Yes, the flak is THAT effective even with AirPower, that RUb had to drop the range by so much. Unfortunately, I believe that is as good as it will get.
Myself, I don't mind the low range. On a U-Flak, I managed to pop a dozen planes on a patrol (with RUb range). Even that is far, far above what reality could have been.
The issue is not so much flak power or plane armor, but really the AI - as much the too-good flak AI as the too-poor plane AI. And there's absolutely nothing we can directly do about either of those