Most of these games on the stat page are expected to be played more than a sim. Also there's no other real sim on there. Not even casual titles like HAWX, none of the DCS games, no Take on Helicopters, not even Wings of Prey... nothing.
Personally I believe a well written and emotional campaign would be the best selling point. Scripted, voiced over, maybe even having a few nice cutscenes.
I'd enjoy that and it's what most fan projects fail at. I wouldn't even mind if it was in native language (e.g. Russian / German with subtitles for the Moscow theatre).
But that's another topic
