Automatics are hardly OP. They're are a completely situational weapon, useless at any range except close. Starting with one either removes a more useful perk or removes your ability to fight at any range other than close. If you're having trouble fighting someone who is using an automatic, switch to your pistol. The Boltshot destroys at close range and the Magnum kills faster than any primary precision weapon. I'd say Plasma Pistols are more of a problem for tanks and the Mantis. The true bane of Warthogs and Ghosts are sticky grenades and the ability to call down a Splaser every few kills.