Similar to Legendary Potential, set could have Unique Potential.
or a mechanic allowing the set item to be crafted.
It would be cool to somehow slam a unique onto a set item of the same type.
Or maybe it could be an affix swap.
It could be a new Dungeon, similare to Temporal Sanctum, allowing to put a Unique and a Set item into an altar.
The result would be the set item with 1 of his initial affix swapped with 1 of the unique affix.
There could be a Stage 1 for the Dungeon to target Implicit affix.
Stage 2 to target affix, etc.
Each try would consume 1 Unique Potential.
So you could try a second time with a different Unique for example.
What you think?