I believe that one of the best things you can do as a game developer is offer choice, variety, or customization. The guns are one of the biggest determining factors in the playstyle of this particular game. I propose that instead of locking out a guns damage, keep all of your exotics up to date. This will add validity to ownership of the gun expansions down the road. I could just imagine whipping out the Myhtoclast in Forge of the Gods and having someone new to the game be ecstatic to see it like I am now. I understand keeping weapons in the past but at the same time it pains me to see options disappear.