Even in 0.70 shotgun was random at med-long ranges, especially when the enemy had cover making hitting an enemy a game of russian roulette no matter how good your aim was, allowing 1 shot kills at long ranges with luck, but sometimes you wouldn't get any damage done.
I suggest making the shotgun shoot a hitscan beam that is always the same instead of random pellets. (you could throw in some pellets for visual effect)
The damage your shot does would depend on how far the enemy is and how well you aimed.If you aimed to the exact center of your opponents head you would do more damage than slightly missing the enemies foot (you would still do a little damage because of the spread of the shotgun, but not a lethal amount.)
Not only this mechanic reward you from aiming well, it would also increase the skill ceiling you could achieve with the shotgun.
It would also lessen the times when you are like "1 shot from 50 blocks away with shotty! Poop!"
The beam would be in a shape of a cone
