What can/should Bungie do about Tier 5 weapons?

I've seen lots of posts analyzing what's wrong with Destiny and suggesting improvements, but I don't know if I've seen anyone offer a solution for dealing with the existing crop of Tier 5 weapons. As it currently stands, there's a large segment of the player population that have best-in-class weapons for every slot. And now that Bungie has scrapped their plans for a "seasonal" reset, those weapons are permanently available to them. Not only is this a severe issue with power creep, but it threatens to invalidate future loot chases. How do you recover from that?

The obvious answer is that Tier 5 weapons just stay in the game, and you hope future weapon releases are enticing either from a power or aesthetic sense. But like, what if Bungie went nuclear and sunset Tier 5 weapons altogether? I know "sunset" is a loaded word within this community, and this would likely be a huge blow to player sentiment and trust within a game that's already struggling in those departments. But at what point do you have to look out for the future of the game (whatever that may be)? The existence of Tier 5 weapons was inherently tied to the reset model originally proposed, but with that reset cancelled, I just don't know if they should exist in a game that's no longer going down that route.

So, what do you think Bungie should do, if anything?