First off. Sorry if referencing another game is against the rules. I mainly bring it up to add context to my post. If it is a violation, then please accept my apologies and remove it.
In Elder Scrolls Online, there is a vendor that appears every Friday in Cyrodiil (the PvP area) that allows you to purchase set gear. Every week, the items are random selected to appear. They are usually overland jewelry piece and a monster helm or shoulder. They are purchased with currency that you gain in Cyrodiil called Alliance Points (AP).
From watching the live stream. It sounds like they are coming up with a similar concept. A vendor that appears every week with a random piece of gear that can be bought with a specific currency.
So what are your opinions about this new vendor? Personally from my experience in ESO, I think it's a great idea from what they put out in the live stream. Yes we will need more information on it and see it in play to get the full feel of it. But I like the concept seeing as it is similar to another game systems concept that works.