With the realization of the amount of effort that now goes into improving a legendary item and the fact that it may well be all negated with the next level cap increase, some serious thought about revamping the system needs to be undertaken. Here are some simple suggestions for a revamp that I believe would solve most of the underlying problems with the current system.
1. Allow barter for +1 equip level scrolls. Make these require a substantial number of skirmish marks and/or other barter items. The DPS and any other relevant item statistics increase with this equip level.
2. Get rid of the First/Second/Third age language. Make them good/excellent/superior or something like that. Allow barter for scrolls that upgrade the quality tier of an existing legendary item, but make them require a very large number of barter items or rare drop. Certain base stats (like dps) should increase with the increase in quality.
3. Get rid of world drops for legendary items, and make legendary fragments barter components and all legendary items crafted. This would give crafters something to do. Make crafting excellent or superior items require a very rare component, as they do now. Make settings world drop as the number of deconstructed "legendary" items would be substantially reduced.
4. Continue the legacy replacement and upgrade scrolls, but add scrolls that replace an undesirable legacy with a pick of two random pulls from the legacy pool that the item does not currently possess. Consider adding upgrades beyond tier 6 and possibly legacy "addition" scrolls (starting with tier 1), but making these very hard to obtain.
This revamp would solve several problems at once. It allows people to keep their existing items from expansion to expansion if they so desire. It allows continual improvement of items as time goes on. It keeps in place a mechanism of giving people something to do each level cap increase if they already have the "perfect" legendary item (i.e. the equip level would still need to be upgraded). It also uses many elements of the existing system and on paper does not seem like a major overhaul.