Last night i got the Merciless exotic fusion rifle. When i read the perk description i was like meh. But holy crap, it's a cool weapon. The first shot takes forever to charge but each shot that doesn't get the kill makes the next one charge faster. It's not OP because power ammo is limited. And it doesn't affect pvp.
gun is a dps machine for pve and i know bungie is going to nerf it
make merciless a hard requirement for raiding. you'll enjoy your hot dog barbeque