I'd like to see it remain a permanent addition, with just one change...
Instead of a renown track, just have a Plunderstorm shop where you can spend you accumulated loot, so instead of having to grind to get the things you want, you can pick and choose the things you want. Over time, Blizz can add more and more stuff to it. Basically, the Tender shop without monthly rotation on items. I wouldn't mind if it was on rotation though, to be fair.