No you can't. You just came out of a firefight. Some douche comes barreling at you from around the corner and simply double (or single) melee kills you. How is that defensible? You can't explain that.
[/Bill O'Reilly]

By contrast, same situation in Halo 1: guy hits you, you recoil and throw a plasma grenade. Most likely you both die. At best you kill him and survive. At worst you miss the grenade and get killed or kill yourself.

It's not the armour abilities. It's the over powered melee, the melee lunge, the bloom (to a small degree, but not much), and the reticle magnetism. Also I swear that the hit boxes are bigger than Halo 1, but I have to see the files.