I've often thought that it'd be great to have the playability and flight models of AH combined with the graphics of IL2/PF. When you fly over the water in PF, it looks like water - not blue shag carpet. Also, there are beaches on the shore, and the water changes color to reflect changing depths, ie light blue next to the sandy beaches, darker blue the further you get from shore.
I also like the variety in the IL2 series - snowy russia, sandy north africa, green jungles - not to mention snow, fog, rain and other weather effects.
I know HTC made an effort on the water a while back with the animated water. I'm not sure if it's just my machine or not, but it looks like quivering blue jello on my screen - I leave it turned off in favor of the shag carpet look.
IMHO, the flight models in IL2 just don't seem right. It's probably becuase I am more use to AH though - I'm not sure what a "real" flight model for a WWII fighter should feel like. Unlike most of the rest of you, I don't have countless hours in my dad's P-51 to compare it with. . . .