Aim-Down Sights (ADS) does not belong in Halo. The definitive guide (work in progress).
Essentially Aim-Down Sights is shorthand for gameplay mechanic in shooters where there are two discrete aiming modes: Aiming Down Sights (ADS) and Hipfire. This is the de facto standard for modern military themed shooters like Call of Duty and Battlefield. By default, the player is in hipfire mode, which allows the player to look around quickly but generally not fire the weapon accurately. To fire accurately, you need to enter ADS which allows for more precise aiming by lowering the effective sensitivity of the controls, usually both the "look" stick and the "move" stick. This is fine for some games built around it. But Halo is not one of those games.
Halo gameplay (and this is pretty much all from a multiplayer perspective) is built around a golden triangle, where using traditional weapons is still very important but also where grenades and melee are vital to success. Halo also has longer kill times in general which make tracking other players in a battle more important since you have to apply damage to them over a longer period of time.
Since there is no real ADS barrier to aiming, players are more mobile while they fight, making maneuver during a firefight important. You can duck behind a pillar or jump to throw off a burst. But most importantly in my opinion, the lack of ADS means you can smoothly transition to other parts of the "triangle" instantly. There is no artificial choice between aiming your gun accurately and doing anything else. You can throw a nade at a wall to explode under a player chasing you and whip around and immediately start pouring bullets into his or her face and finish them off with a punch to the throat without having to enter what amounts to "shoot gun mode".
Halo-style, there are way more diverse choices available to players in most situations, and they aren't automatically screwed if they turn a corner and an opposing player is already ADS'd in down the hallway. Battles are decided more often by skillful use of movement, consistent aim over time, and exploitation of other parts of the triangle than first-shot accuracy. The lack of ADS also means that since players aim isn't boosted at medium or long ranges, they have an incentive to close the range where other parts of the triangle shine. That makes for more diverse and interesting encounters. This is fun (tm). If you do not find this fun, Halo is not your game.
You might hear people say Halo games already have ADS. Not really, in true ADS games the vast majority of shooting encounters involve ADS. In Halo zoom, even if available on the equipped weapon (which you cannot assume), is useful only in a subset of long-range encounters and is more clearly disadvantageous in short-range encounters (since long kill times require you to keep on-target longer).
People have suggested making ADS optional or purely cosmetic... Why? There is no point to have a feature that does not affect gameplay (which I'm not sure is even possible since it's at the very least going to mess with your view) but removes a button that could be used for something actually interesting.
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It's late, I'm tired, will re-read and prolly edit tomorrow, feedback welcome. I will be linking back to this whenever someone brings up how Halo should be Call of Duty but with power suits (and aren't they fucking making that already?).
