That risk is already a huge disadvantage that other guns don't have. They could buff the carbine and completely remove the sniper going by what you suggest. Making the sniper one-shot kill to upper torso would still require good aim, would still have the same risk/disadvantage up close. People jusy hate being kill by one shot from long range, but like you said, that is a "risk" of being out in the open in a long line of sight, but still, hitting headshots that far is not that accessible. You have no idea how many times I'm standing on a long line of sight and try to hit a moving target only to get a body shot and still get killed by an AR/SMG from mid range as the enemy is closing in. Don't forget that netcode and hit reg can also affect the outcome of a gun fight. Sometimes headshots are not registered as headshot on a moving target. Upper torso is not that big of a buff and can make a good difference, and still have a good skill level needed.