Currently there is little use to re-running most of the dungeons. You can farm Abyssal Meat in Dregs, though the decay timer now works correctly. Maybe you need a Heart of the Kinscourge for equipping all your thralls with Telith’s Sorrow. You used to be able to harvest a significant amount of Demon’s Blood from the Barrow King, but either my RNG is bad or it’s been nerfed.
A simple idea came to me today to encourage players to repeat this content - add Legendary repair kits to boss loot tables. I admit that these should still be rare and all bosses are fairly easy to beat if you are specc’ed correctly, so maybe the drop rate is low, like 1-5%. Whatever Oscar and Joel feel is an acceptable quantity of these kits to add to the server economy.
I admit I haven’t played with the new Purge changes on Testlive yet, but it seems like having a reliable way to get these, even with a low percentage drop rate, would make some players feel more comfortable using their favorite Legendaries.