I've always felt that because the aircraft of WW1 operate at airspeeds so much lower than the WW2 variety, the game engine could use much more of its power to due "other" things.

The level of detail for the a/c and ground objects could make PF look like RBII , and the ground action could be a very active, integral part of the sim. Fancy sound effects eat up a fair bit of power, but again this could be emphasized in the game.

Copterdrvr