I found in BF3 going prone was pretty handy in some tight corners and open fields. Traditionally Halo never had this, but Destiny isn't Halo, and going prone might be a needed ability when using some of the larger suppressive weapons or sniper rifles. Plus the benefit of conserving ammo if a player needs to wait out a Ai while being in a smaller detection box could be a life saving tool in the player kit while abroad in the open world.
Also I wouldn't mind some sort of climbing animation for players as well, so we can scale walls with say heavy foliage growing on it. This all plays to the Hunter class, but I could see it being universal only lets go with Titans climbing slower than both the Warlock and Hunter, while the Hunter is the faster of the three.
So if anybody remembers playing Turok I wouldn't mind some ability to leap across a chasm and grab onto a wall of vines and scale up the side of some Fallen Fortress to get the better of them.
-
Prone not only doesn't fit with a fast paced game, but there are design challenges the developers have to overcome (or deal with the subsequent glitches) that prone comes with. Spaces where your character standing or crouching can fit in, but being prone cannot. Inclines you can walk up but can't crawl up (stairs) without graphical issues or at all. Going prone on a 3 inch wide rail. Now, those are some technical and graphical issues that can arise with prone. Player frustration can arise when a player wants to crouch, but accidentally goes prone, and ends up dying because of it. With crouch being assigned to the same key as prone, one could choose one when they meant to choose the other, and subsequent consequences can come out of that, and the player experience might be bad for the player. Where if ONLY crouch were mapped to the key, the person wouldn't touch the button if they didn't want to crouch. They would only touch the button if they wanted to crouch.