I think the simplest and easiest way to improve graphics is to have the option of an even higher resolution texture pack. In some planes, you can't even read the labels and warnings, while bolts and rivets look like a gray mushed dot. For example, my 109K4 pic on the first page. Looking at the wing, you can barely read the warning sign and the bolts, well I wouldn't even call them bolts.
Planes should get the best visual effects, followed by weapon visuals (smoke, fire, tracers) because that's what we see constantly in game.