Your list is lacking the father of modern combat flight sims, Falcon 4
I've been "simming" both F4 and IL2 since they were published. Today's F4 is quite far from the original, published in 1998(?). Extensive modding has been possible due to a leaked source code, and hence they have been able to touch issues like the graphics engine, something SH3&4 modders can currently only dream about.
My HD houses currently:
Falcon 4 Allied Force
Open Falcon
IL-2 1946