Mythic Affixes on regular Unique items.
Wouldn't it be cool if Uniques had chase affixes beyond your standard "+ Skills"?
Unique design is so boring because 90% are just designed for a specific interaction with just one skill....So at least make them exciting in some way.
Uniques should have 3 potential "Mythic" Affixes, of which only one can be on an item at a time.
Take "Sidhe Bindings".
You could now find a Mythic Affix which is:
"Familiar summons are now permanent".
or
"Summoning a familiar increases your damage with Cooldown skills by x% for x seconds"
or
"You can now summon 12 Familiars and skill duration is increased by x%"