Beanman,
I hunt alot of tall sagebrush and I have never had a problem with snagging. I think you are smart considering all these things though. If the mesh was saggy, I bet it would snag, but it is pretty thick mesh that stays up against the pack nicely. Some people laugh at me because I am so into packs, but I'm telling you, after trying several different ones, once you have a well thought out, comfortable pack that works for you..it makes you a better hunter. If you know exactly where everything is, you wont be fumbling around when it counts. You dont need these huge packs even for packing out animals. Just carry 2, lightweight, durable game bags, tie a knot at the top of the game bags and a foot or so of rope(depending on how broad your shoulders are) and you can pack as much meat out, hands free, as the guy with the bigger pack.