I stopped playing IL2/FB because of lack of immersion.
I still really like IL2, but immersion is very much missing.
IL2 has a sterile generic map, cartoonish look and feel, few enemy units (considering the scope of WW2), a very generic "dynamic" campaign engine, etc ...
Falcon 4 had more immersion, because of its dynamic campaign engine which gave the impression that you were in the middle of a big fight where flights were taking off 'round the clock.
Anyway, I'm looking forward to Black Shark which will push LO forward in the right direction, although perhaps a bit slower than we would like.