Like exotic armor allow us to reforge current armor in order for us to achieve the desired character look we want while allowing us to alter the other combat perks / stats based on our current or evolving play style. There is nothing worse than having 10 versions of Iron Banner Chest armor and none of them provide ammunition for the weapon you use most or the correct intellect/discipline/strength combination you are trying to achieve. It makes the game a lot less fun when you have to sacrifice preferred combat or desired appearance because more times than not its one or the other. Additionally if I decide to adapt and change my playing style I now have to forego my favorite piece of legendary armor (not easily obtained in most cases) because I can't alter the stats. ...I believe that this would also help to reduce the amount of vault space required for each character. For instance I save over 15 different variations of Titan chest armor so that when he is a Striker he can max out Discipline and strength.. But if I want him to be a Flaming hammer of death I want to max out his intellect and discipline to maximize the perks of that subclass and my tactical play style. And the longer you play the game and become more experienced you want to be able to fine tune this ability to change Armaments without completely destroying the look / persona you have worked long long hours of grinding to achieve. Furthermore If all three characters are used/played this way vault space becomes filled pretty quickly. I absolutely hated and have regretted deleting some armor pieces that I decided would have been very useful later from hard to obtain activities like the raids or lighthouse because I couldn't reforge them and I didn't have the vault space to hold on to them.