Well, there's another problem with that whole .50 BMG round. This game will not use any sort of weapon that comes close to using this massive of a round. I'm getting extremely tired of saying this, but the bolt action sniper rifle in this game does not in any way represent a Barret .50 Cal but actually represents the http://www.youtube.com/user/BrinkVideos#p/u/0/l_CykYOy6Lw. The only reference to it is during sound production, as this rifle may use the sound of the Barret used in testing (and even that's unconfirmed). In fact, not once is ANY sort of name confirmed officially for the bolt-action short rifle. If you look at the round used on the website, the real SR-93 uses the NATO 7.62x51 round. I'm not going to go into technicalities because there are no actual bullet sizes in Brink.
It's not so much the size of the round as the impact it imparts on the body. Getting hit center mass by any sort of long-rifle will do more damage to the muscles and bones around the point of impact than, say, a pistol or sub-machine gun. Cracked ribs, torn muscles, ripped organs - it's safe to say you won't be getting up and fighting after a hit like that, so in game terms, one hit kill.
I'm not a rabid proponent of OHK's with long-rifles, most specially after I read the interview that mentioned the developers stance on them: take a big chunk of HP out of your enemy, finish them off with a secondary weapon. However, I will point out the joke of an argument that 'hardcoe' modes are somehow ruining competitive game play - shooting 20+ rounds in center-mass to secure a kill (talking BFBC2, CoD: MW1/2/Black Ops, BF2; NOT BRINK) is ridiculous and counter-intuitive to what is seen in a competitive setting.
Complaining about camping*? Camping is a joke to avoid. If it's a crap map, learn all of the high-travel spots and always check them. If it's a good map where there are too many solid 'camp' spots to learn/check? Don't run straight in to a room and cry when you die to someone in a corner, window, or adjacent building. Talking down camping just shows you're not a good player. I mean, sure, camping on some maps (Black Ops, what a joke game) is derpherp to be successful with, but let's be honest: the reason camping is successful in a game like Black Ops is because of the fairly limited movement around the maps. You can be inventive with jump, crouch, and prone, but good luck actually doing much of anything with a flank.
Guess what'll probably solve that? SMART, and not just SMART, but the freedom implemented in Brink with the inclusion of SMART. As one recent interview stated, SMART isn't as much about giving experienced competitive (read: played in ladders) players a brand new way to move around the game world, but giving less experienced/competitive players an easier time of it while also insuring no player will ever be blocked by a friggen' table or chair.
Brink's going to be good, but OHK/Camping has it's place and the very sentiment of, 'lol hurpadurp SKILLESS CAMPING NOOB WTF ONE SHOT KILL SCRUB" is wildly entertaining and incredibly sophomoric.
*not just referencing the quote, but the OP as well.