Gauss in proper hands is IMBA gun.
Thats not good idea, to make BG weaker. Lets think about real pvp between guy with sniper rifle and BG guy. Do your really think that sniper can make 2x eyes aiming shots, while bg can hit one burst? No sense at all.
Just use ur range - play ur build right.
ability to have a chance to chose spawn point would solve it all.
In an open space encounter you still resp (with 12 pe) in the middle, so don't tell me about terrain.
Also I still hope the game will ever be possible without action points in RT and things like aiming time would ever be visible. (eg. 7AP shot would take nearly twice as much time as 3AP shot to go off) So that it makes sense to have various AP costs.