Because---now that ARs have been needed into non-competitiveness, and shotguns have had their ammo severely restricted--people aren't stupid. They're are NOT going to stick with weapons that are now a handicap. They WILL move to the NEXT most competitive weapon in the close-to-midrange combat that The Crucible maps foster. Thorn is powerful and one of the best, most balanced performing weapons in the game right now, since ARs have been wiped from the field and pulse rifles are not reliable at close range. Thorn is the same weapon (ignoring the subtle range nerfing) that it has been since December. It didn't magically become OP overnight. What happens is that patch 1.1.1 [i]drastically[/i] changed the weapon balance, and the meta shifted to accommodate. ARs got crippled and lost the ability to dominate close-to-midrange fights. At first shotgun rushers expanded to fill the vacuum created by the imbalance. Then Bungie clamped down on special ammo to rein in the shotgunners. So now that their two primary nemeses have had their fangs pulled, hand cannons are now filling the vacuum. TLDR: Thorn isn't OP. The problem is 1.1.1 destroyed the balance at close-to-midrange and each nerf is making it worse and narrowing weapon variety. ARs need to be buffed back to their pre 1.1.1 damage levels. Personally I use whatever is competitive, and suits the situation and character I'm running. Which means I rotate between several different primaries. One time I'll be in your face with TLW. Others I'll mix it up with Bad Juju and Red Death. Others I'll be blowing your head off from long range with Mida and sniper rifles.