I think the swords need to be made a close range heavy weapon, where the heavy ammo gives you time (e.g. 1 pack=30 sec) and the sword have quest lines to receive them like the exotic bounties (where you do the sword of Crota mission, defeat blades of Crota, and kill a certain number of enemies with swords) and doing so gives you a sword with random sword perks (such as larger shock radius for the jump slash, or regular attacks dash farther)