I'd prefer a post-BOB Western Europe first of all, let's say 1941 - '42. This would include a few new fighters and some AI bombers and a somewhat larger Western Europe map (and re-use a lot of objects already there). It would also be the easiest extension to get done while they fix the underlying engine and all bugs reported sofar. It would mean some new variants of Spits and Me's and a nice new FW
BoM is far more radical and a lot more ambitious. New map, new planes and a lots of new objects. In this case there's far more for to do than just fixing the game itself. I understand they like to do this because it's a Russian game and also would like to see the Eastern theatre included again, but I'm not that convinced they will be able to pull this off in 6 months or so.
First they'd need to radically improve this game and bring it up to a state where il2 4.11 stands now. Graphics are the least of their problems right now; they are already great and highly detailed, but there's a lot more than just eye-candy.
Rgs,
FP