Yeah, sniper is a very important class, if played right. Sniper is not about 1337 kills, it is about defending key positions. Sniper is worth it if only to kill heavies and medics.
But more than 1 sniper on your team will make you lose, every time.
As a sniper, the enemy sniper is your first priority. After he is dead you have around 20ish seconds to shoot medics and whatnot, and then he'll be back.
We played dirtwork yesterday, I thought it was pretty bad. In fact I sat by the intel in base where there is a health supply and was invincible+unlimited ammo+guarding the intel.
Dustbowl however is classic and one of the best maps, if not the best. It is hard to defend, unless you have a good build and a smart team (usually too much to ask for).
http://www.fpsbanana.com/maps/36321
http://www.fpsbanana.com/maps/39398
http://www.fpsbanana.com/maps/36292
some custom maps that might be worth checking out...