The season 4 itemisation changes are great, but the relevance of the game’s unique items amidst these changes is something of an elephant in the room. Most are useless, owing to their affixes having been conceived in a world where affixes more broadly were significantly less potent, but even a complete rebalancing of every unique in the game to bring them in line with the affixes that now feature in that gear slot (e.g. attack speed on rings) would still leave them largely irrelevant given the potency of master working.
One option is of course a last epoch style system, where you can combine a tempered item with greater affixes with a unique item, replacing the item’s legendary power with the unique item’s unique effect.
My preferred solution though, which would be not only simpler to implement but much more in keeping with Diablo’s legacy, would be to bring back Kanai’s cube from Diablo 3 but ONLY for unique item effects.
Let us be able to salvage unique items, and add their effects to a separate tab of the codex of power, and choose one weapon, one jewellery, and one armour unique effect to have equipped to our character at all times. Have it work similarly to the codex of power, where unique effects equippable via the cube can be improved by salvaging items with higher rolls.
If Uber uniques are considered an issue, give us the option of having one Uber unique effect equipped, at the expense of not being able to additionally choose a weapon / jewellery unique effect (assuming shako).