what he said.
besides wind direction, long ranged shot are also affected by gravity, the bullett wont fly straight forever, and eventually lose its strength. maybe that could be another added feature to bullet physics.
about the wind direction. you could put slight animation on flags and plantlife that follow the wind direction. then again, the sky is also a good thing to look at for wind. it would be good to put the hi-res skymaps to good use for snipers. it can be programmed to follow a generated wind pattern.
also, part of physics, bullets alo slow down, eventually anyway. and if you shoot it up at near 90 deg, its bound to come back right at you. the bulet shoud do more damage if it is flying downward, being aided by gravity and all, but that normally only makes a diff if the shooter is really high. plus, the volume of the air can also affect the way a bullet does damage, since thicker air mass can slow down a projectile, but only to a slight fraction of diff.
maybe this is alittle to much on physics huh? but real snipers have to deal with these factors, so it might be nice to have it TC:E.