I don't know if it's possible, but why not add another mod slot to weapons? In this slot, you can add perks from a new pool of weapon mods that drop at random in the wild with drop rates base on their quality. You can get these modification from anywhere in the playable PVE area or as rewards from a crucible match. These could be perks such as Third Eye, Lightweight, Grenadier, Knee Pads, Counterbalance or Battle Runner. They could be exotic or legendary weapon mods. Pull from the vast pool of D1 weapon perks. I'm sure some balancing and tweaking would have to be done after play testing, but I feel it would add something to grind for and give an easier route for weapon creation. Weapons could be brought back from D1 as well. Players wouldn't need as many unique rolls for weapons. But players could collect their favorite weapons and then grind for that unique perk for each weapon they found. Weapons could retain their current balance and perks could be adjusted around the current balance.