Extract 1 item of each set in the cube to obtain a slot giving +1 to that set effect. Just like any other cube slot except it’s a set name and gives +1 to that effect.
Example:
I have 4 pieces of a 6 piece set equipped with a royal ring of grandeur, I switch my cube set slot to that set and gain the 6 piece effect.
This would expand build variety exponentially by allowing 1 singular set to have the 2 piece effect WITHOUT ring of royal grandeur and it could possibly open up a ring slot or jewelry cube slot.
I am assuming would be one of the easier things to implement, as there is groundwork for pretty much everything except storing which pieces of which sets you have extracted. The slot is there from season 22 with the wildcard cube slot, the +1 to set bonuses is there in the pieces of the sets themselves (how else would they contribute to item set bonuses) and the royal ring of grandeur.