If people learnt the sniping lanes and didn't aimlessly run around looking for cheap shotgun kills and actually thought tactically it wouldn't be as much of a problem tbh. Perfect example, a sniper is in one of the corridors in this week's trials map one guy slides through the doorway the opposite side, chances are sniper will miss as he won't be expecting it, one of your team mates flanks said sniper sliding through the doorway directly in front of him, making it near impossible to get a sniper kill meaning your cheap shotgun tactics still work against snipers aiming at head level. The counter is incredibly easy, but people want easy kills with the minimum amount of thought or effort going in for them. Hence why shotgunners are whining so much about snipers now.