I'm a big fan of ofp1 and therefore i have some suggestions for ofp2:
Crashs should be more realistic than in part 1, if somebody shoots at a plane there should be different consequenzes, the planes smokin, explodes or is only bad flyable. and the pilot should only be dad if it explodes but if it falls down the player should live as long as the plane is in the air. and if the plane is that damaged that u have to land it should be very difficult as in the reality,
and please make a much better multiplayer mode! the multiplayer mode is the only thing that keeps a game for a very long time alive. and if somebody wants to play online and everbody needs his own cd key he has to buy the game but in the singleplayer everbody can use one cd key so u see its also good for u!