Maybe its more about nerfing critical hits then boosting big gunners, how about removing the eye location? The famous instant kill that brings you to 0 (Even tho you are wearing a BA, have 250 hp, and got shot by a bb gun.) ?
Thing with crits is that they take at least a little skill. I personally love the fact that you can try to position yourself in good spot to maximize the chance to do eyeshots. In addition the way crits aren't dependent on your wealth is really great and should be extended to every build and weapon. What's wrong with crits are the ridiculous randomity and awful effects. The effects vary from instakills, -20 ap knockouts, various cripples to zero damage. Especially instakills and knockouts are terrible and shouldn't exist at all. A player doesn't deserve to put someone in totally miserable state by just clicking him once and getting lucky.
Random crits were okay in fallout singleplayer because being a total badass, the chosen one could afford random failures and hilarious effects. He didn't necessarily die if he failed to cripple someone's arm.
A word about instant shot delivery. The fact that no time is required before the shot is launched after clicking the enemy causes problems in this matter aswell. Even if you attack a sniper from behind, he can eyeshoot you in the matter of the time it takes him to click your char.
Yet another problem with crits are that they pretty much always hit with 95% chance and there's nothing you can do about it.