Just to clarify upfront, this post is not regarding Veteran Rewards. Instead, I am speaking of reward systems such as the puzzle boxes, BODs, fishing and the like.
What I think would be a boon to these systems is if every six months or so, you took out some of the existing decor rewards (such as paintings, pillars, stretched hides, hanging tapestries, and the like) and replaced them with new items. Now, maybe in a year or so, you cycle some of the older items back in so that they're never gone for good, but something new is always added to the system in question.
My thoughts are that shipwreck paintings could be replaced with new paintings; hanging tapestries with new hanging tapestries; and so on. It might even be that each system only replaces one or two items every six months (or heck, one item every three months), but the upshot is this: there becomes new reasons to do these particular systems, old rewards become more valuable (though the really old ones never may gain any new value), and systems are revitalized without having to redesign an entirely new system for it.
What I think would be a boon to these systems is if every six months or so, you took out some of the existing decor rewards (such as paintings, pillars, stretched hides, hanging tapestries, and the like) and replaced them with new items. Now, maybe in a year or so, you cycle some of the older items back in so that they're never gone for good, but something new is always added to the system in question.
My thoughts are that shipwreck paintings could be replaced with new paintings; hanging tapestries with new hanging tapestries; and so on. It might even be that each system only replaces one or two items every six months (or heck, one item every three months), but the upshot is this: there becomes new reasons to do these particular systems, old rewards become more valuable (though the really old ones never may gain any new value), and systems are revitalized without having to redesign an entirely new system for it.