It's a great little BFMer. It has plenty of functionality right now, with more to be added obviously.
The flaps issue is known and will be addressed (in what manner, I don't know since I don't have documentation on hornet behavior, but the pitch down should be prevented - this amount of pitch down is insane). Other aircraft, like the F-15 have it as well but it's a) not so severe and b) compensated for by the flight control system.
How did this get missed by in house testing?
There was only 16 squadrons of RAF fighters that used 100 octane during the BoB. The Fw190A could not fly with the outer cannon removed. There was no Fw190A-8s flying with the JGs in 1945.