As someone who never really played a flight simulator before, I certainly enjoyed this game quite a bit, especially since I don't have a good gaming computer. That's what my Xbox is for, right? I bought this game second hand so I certainly feel as though I've gotten my money's worth out of it.
I really enjoyed the ground attack missions in this game, but it seemed like the only plane available for this purpose was the IL-2. I understand that it's the titular aircraft of the game, but I'd really like to see some more medium bombers and fighter bombers. Lots of people have probably already recommended the P-38, but I'd like to see the A-26, De Havilland Mosquito, Henschel Hs 129, ect. More tank killing missions please!
It would also be nice if you could play single player 'training' missions with ground targets, so you could play around with all the awesome aircraft in your hanger, get used to the different bomb sights, and practice dive bombing. Simply dropping bombs from the cockpit view was quite difficult, but dropping them with the magic crosshair bomb sight seemed way too easy. A cockpit mounted bomb sight view might balance this out.
I have yet to play multiplayer on this game, and I probably never will, since I own the Xbox 360 version and apparently there won't be a patch for it. I've tried to find a game, but have never had any luck. I love unlocking things in games, but it annoys me that some of the planes can only be unlocked through multiplayer mode. If you make planes and guns unlockable in the possible sequel, please make them rewards for completing single player missions!
I'd also like to see slightly more attention to detail in the weapons descriptions, although I tend to be quite picky about that. The Hurricane had twelve 7.7mm (.303) machine guns, not twelve 12.7mm (.50) machine guns.

Wikipedia and Jane's are your best friends when it comes to pointless little details like that. I know it doesn't seem like much but I love seeing games where people put in that little bit of extra time and effort.
Cheers and thanks for the enjoyable game.