The difference is though, with those games, there are a lot of different types of weapons That comes out with each new expansion. Here, there are 4 new primaries, 3 new special and 2 new heavy, with each new raid, and usually 1-2 exotics and a raid exotic. All have the same perks and same elemental damage. If it randomly rolled perks and elemental damage like it does for other legendary weapons, then there would be no need. Or if they could come out with a weapon creation/modification system where you could assign points to the different abilities like ROF or impact, reload, stability, etc... Then there would be no reason for upgrading previous weapons. But as it stands, right now, everyone gets the same perks and abilities and elemental damage on the same weapon. So, for me at least, I still use my fatebringer and VOC a lot due to I like the perks and stats, the only thing about them I do not like is the decreased attack level.