Fourth level of gear above Unique: "Enegmatic"

The entirety of the suggestion is too large to post here (it goes past cap limit), so I'll have to link the screenshot of it here:

But a quick summary is that a fourth level of gear above unique called "Enigmatic" could be acquired in Apocalypse +, with its main quality is that it has a 4th enchantment slot, and the top enchantment slot would have anything considered "powerful" as well as several unique enchantments I described in the screenshot above.
This would be a great way to balance the higher difficulties in Ap+, and reward/encourage the player to take on greater challenges