Having been to Rhinebeck several times I can understand where Travers coming from.
I read and understand the release notes, the main issue is that in game they still sound very smooth and "throttled". If you have been to Rhinebeck and hear the actual rotary engines they sound very different when the cylinders are cut out.
The rotary engines are modeled correctly it's just that the sounds are not accurate. I suspect it world be much more complicated to manipulate the eng.wav for partial throttle on a rotary then just simply changing the playback speed. Maybe someday in the future it can be addressed, but I suspect it will be a while.
As a side note, I configured a button on my stick as the engine on/off switch and use that instead of the throttle (leave it at 100%) for the Dr.1 and F.1 and it works great!