In my opinion, this is how I see the best simulator:
First of all it is a question of point of view, in combat flight simulator 3, you play as a pilot, in il2 1946, you play as an aircraft, me, I agree with cfs3, you create your pilot, his face, his unifrom (like in Cliff of dover) and with all flight, he will improve skills, about G force resistance for example
Display (like cfs3):In scramble, campaign/single missions or multiplayer, you spawn next to the aircraft, walk in airfield if you want and get in the aircraft
MapsDon t forget it s a flight simulator, don t spent too many time on, it's not battlefield or arma, I imagine something like the dcs wwII map about details and texture
What I hate in il2, runway, taxiway, everything is over the map, the main objective should be to mix materials, grass, concrete, earth in one bloc, not different object
CampaignWhat about a dynamic campaign ( like in cfs3 again
), your action have an impact on the campaign and add some historical missions for keeping a kind of reality.
AircraftI'm not severe about 3d, but I prefere having the choice between 20 excellent 3d,FM aircraft, than 200 unfinish aircraft with bad FM, and second point, damage model, like rise of flight or cliff of dover, 1 bullet = 1 impact
I hope I helped this brain storming