Small maps plus Bungie refusing to tackle the core issues that make HCs so insanely potent gets that. They still have too much aim assist, and they also have too much reach for their zoom level and sheer flexibility. Even just swapping AR and HC range with an AA nerf fixes that (and keep 120s where they're at currently but bump the zoom to 16). The maps will never not have shotguns be the general favorite, nerf ammo economy, shotgun output in general, whatever, they'll be the favorite until you get some... Let's say Favela or Warhawk sized maps over the more Nuketown-y type maps we currently have. Not to mention free mobility in the form of Icarus Dash and to a lesser extent St0mps make shotguns and HCsEVEN MORE favored over your Pulses and the like. Pellet shotguns are simply impossible to give a major nerf to, the reality is they aren't actually that good as guns, especially after the most recent changes they had.