The basic intent of the gauss sniper is chest hit = 1 shot kill if the target doesn't have armor mode on.
Now if you hit a part of the box that has less than a 1.0 damage multiplier (legs and such) your gauss will not take out the victim even with armor mode off.
It's slow rate of fire, shows a pretty beam, does a big sound that many of us in c1 has learned to hate then go seek and destroy the guy.
Dsg silenced in skillful hands imo > Gauss.
Let's say Gauss would be a sort of sniper combat kind of thing where you don't necessarily want to use scope and HAVE to move around because of the DANGER BEACON you are going to become

Although I give you props for attempting to snipe with a gamepad. Probably makes you think 5 times more about your positioning. There's some good in the gamepad... You gotta learn to give yourself the odds of success a lot more.
I'm not sure there is anything needed to be fixed with the snipers. Although someone wrote in a post about the gauss spread being frigging crazy. Dunno if I should unlock it... ^^
EDIT: The Gauss damage is 115 and the armor mode soacks 35%. check http://denkirson.xanga.com/742784256/crysis-2/ for the weapon and nano modules data.