Every radically new aircaft has its teething problems. I remember there was a series of crashes of 737 aircraft when they were new. And it wasn't even "radical".
The "ring vortex" thing, or what I was taught was "descent with power" will happen with any helecopter type aircraft. Just like stalling a fixed wing aircraft will bring it down if no recovery is made, "descent with power" was purely a pilot screwup and can't be blamed on the aircraft.
If this thing wasn't radical, and there weren't politics involved, no one but those involved would have paid attention to the crashes.