There's a simple solution. Make all weapons and gear in fusible to whatever the current cap is. If you want a specific VOG weapon, then do the raid and infuse it with a current light level weapon. This would give new players and old a reason to want to do the older content while still needing to do current content for the gear in which you would use for infusion. There is no reason to change any of the mechanics or story line. If not this, then in my opinion make all exotics, or at the very least those which were awarded as raid specific (mythoclast- necrochasm) or awarded through bounties and quests (Thorn, BJJ, Pocket Infinity) able to be infused.