Recently Relics of the Past were datamined which is an extremely intriguing item. Using these as an optional reagent you can upgrade the item level of old expansion crafted items to make them a specific item level. This includes boosting the vendor sell price, which can make new vendor shuffles work!
Crafting the relics
There are 5 tiers of relics of the past, and they can be crafted with materials from every expansion. A relic of the Past 5 can be crafted with cloth, leather or metals, with recipes for each specific expansion. Cloth and leather will likely be the best options, particularly using BfA leather, which is the extremely abundant Tempest Hide or using some of the cheaper old world cloth like Windwool.
In either case the craft time right now is 3 seconds, which is actually not that bad.
You need to use the relic with a recipe from an expansion. I have not tested this myself, but it should be useable on an extremely wide variety of items. In the current PTR build sockets scale incredibly well, and getting crafted items with sockets will make you very strong. It’s uncertain if this is intended, but it could be a nice niche to sell to players looking to powerlevel. This could make certain old epic crafting recipes quite valuable.
Either way this kind of gear should completely displace uncanny gear as the go-to gearing options, so prepare accordingly. This could also kill the market for crafted transmog for some of these expansions as you can get two birds with one stone when gearing a new alt (if there is a reliced item on the AH).
Vendor shuffle potential
For vendor shuffles you will of course want to focus on the cheapest items possible. An early example is the brown Linen Pants. With the relic of the past with runecloth you get a break-even price of about 5 gold per cloth. Currently the EU region price is 1g for Linen and 2.35g for Runecloth. This would be quite a nice vendor shuffle in terms of profit. The time investment and getting enough materials at low prices will likely be the two biggest hurdles to doing this in large quantities. We can also expect that Blizzard will change this if the shuffle gets widespread, as they have typically nerfed raw gold generation in the past.
Relic of the past 4
An intriguing possibility is items that you just upgrade with the 4th rank relic. This one has a cast time of just 3.5 seconds. The vanilla relic for tailoring takes 5 mageweave cloth, which should be in the same price level as the runecloth, or even cheaper. The vendor price increase is lower, but you get 3 items in the same time as you get one with the 5th rank relic. If you can actually get significant volume this will be the way to go speed up your time as much as possible.
The final word is not out
We don’t know how it will actually look when it goes live, so we will have to wait and see. It’s all speculation based on PTR and beta at the moment. I don’t expect Blizz to let us play with an overpowered vendor shuffle, so I expect some nerfs.