On the Barret, yeah it's powerful but it's overkill. It doesn't have a use, other sniper rifles have just as much range and don't weigh as much as a small country and have bulky magazines etc. Also it won't penetrate a tank, it might penetrate the side/rear armor on some weaker APC's but it's a .50 cal round, most armored vehicles are protected against them. Funnily enough it was designed to disable parked aircraft rather than be any kind of sniper rifle.
But in a game like MW2 the snipers shouldn't kill in one body shot, or arm shot. They should kill in one headshot otherwise whats the point of even having the 'headshot'. The game is just dumb, generally the difference between bodyshots to kill and headshots to kill is 1 bullet or 0 bullets, and with the assault rifles that fire 900 bullets a minute the difference is nothing compared to connection latency, so you get a game where the decider in combat is latency. Not a good thing.
As for the idea of bullet drop/wind. In a game like MW2 it's totally pointless, it's already horribly unrealistic so it would just seem out of place to add in ballistics, the biggest areas are about 100m across anyway so the travel time and drop of a sniper round would be completely insignificant. If you want a game where sniping is actually sniping play ARMA 2 or ARMA 2: Operation Arrowhead, or both.
As for the Models being realistic? I invite you to fire military grade shotguns duel wield at arms length. You'll shatter your wrist bones on the first shot, it's simply not feasible. Also if the shotguns are going to be realistic then make their penetration realistic, they do very little to body armor/kevlar helmets since the shot doesn't have much energy but it does a lot of damage over an area. That's pretty much the reason why soldiers don't use them, and the spread should be a lot smaller, at the ranges in MW2 where it's fully spread out the spread should be about the size of a tennis ball. Also one shot of an AK-47 should take off an arm/make you bleed out on the floor horribly and totally immobilise you.
Games like MW2 portray war as 12 year olds like to think it is, you run around firing your assault rifle from the hip and playing like your on crack cos it's totall E1337. In ARMA 2 if you misjudge your positiong, your stance or the strength of the enemy you will end up dead.
But in a game like MW2 the snipers shouldn't kill in one body shot, or arm shot. They should kill in one headshot otherwise whats the point of even having the 'headshot'. The game is just dumb, generally the difference between bodyshots to kill and headshots to kill is 1 bullet or 0 bullets, and with the assault rifles that fire 900 bullets a minute the difference is nothing compared to connection latency, so you get a game where the decider in combat is latency. Not a good thing.
As for the idea of bullet drop/wind. In a game like MW2 it's totally pointless, it's already horribly unrealistic so it would just seem out of place to add in ballistics, the biggest areas are about 100m across anyway so the travel time and drop of a sniper round would be completely insignificant. If you want a game where sniping is actually sniping play ARMA 2 or ARMA 2: Operation Arrowhead, or both.
As for the Models being realistic? I invite you to fire military grade shotguns duel wield at arms length. You'll shatter your wrist bones on the first shot, it's simply not feasible. Also if the shotguns are going to be realistic then make their penetration realistic, they do very little to body armor/kevlar helmets since the shot doesn't have much energy but it does a lot of damage over an area. That's pretty much the reason why soldiers don't use them, and the spread should be a lot smaller, at the ranges in MW2 where it's fully spread out the spread should be about the size of a tennis ball. Also one shot of an AK-47 should take off an arm/make you bleed out on the floor horribly and totally immobilise you.
Games like MW2 portray war as 12 year olds like to think it is, you run around firing your assault rifle from the hip and playing like your on crack cos it's totall E1337. In ARMA 2 if you misjudge your positiong, your stance or the strength of the enemy you will end up dead.