This is what I propose:
Make Blackthorn’s drop rate equal to that of a Primal. You’ll still have a chance to drop non-Ancient, Ancient, and Primal. When you land a Primal and only a Primal, you can slot it into four slot in Kani’s Cube.
When you slot 2pc, and 3pc, you get that bonus 2x it’s stats, 4pc immune to ground effects and your choice of any Legendary Gem imbued to the set that can be interchanged with any other Leg Gem, but when you remove said Leg Gem it is destroyed.
You CAN NOT reforge Blackthorn items.
What do you all think?