Game specific weapons?

I think that somewhere, maybe later in infinites lifespan, we should get weapons from individual games, like if I wanted too make a custom game with the Reach DMR and the CE Pistol or the Halo 3 BR with the Halo Reach Shotgun. That type of thing, basically just bringing the weapon sandbox from other games into the game. What do you think about this?

They did that a little bit in 5, but they didn’t do many weapons. I’d love see all old weapons in custom games so it wouldn’t affect the balance of the sandbox.