Too much suppression into a general direction of a sniper and you will just ruin his day, but the actual situation comes when you try to fight back a Sniper/Recon from far away distances... I could see the Idea of try to suppress a sniper but that should be something just when the Sniper/Recon is in another class other than "Recon" class, so you could stop seeing Assaults with Ladder+Beacon at the rooftops sniping as you mention before...
Back in BF3 when suppression had a mitigation way it was much better a solution blurring the screen from a sniper trying to shoot, but not affecting his aim at all... just making the "pressure" and "suppressing" the player.
This should be a game of rock/paper/scissor/'fkngexplosive', you shouldn't try to kill a sniper with an Assault/Carabine, even less with a SMG/PDW, but increase the Suppression Factor as before with LMGs so OTHERs could kill a Sniper it could be a solution.