Breaking down the UR set:
Slot expanders:
4/20 (20%) are slot expanders / slot traders. 3 of those are new tokens, and 1 is a reprint. This feels heavy on slot expanders since there are currently only 6 total expanders / traders (charm necklace, charm bracelets, Earcuff of Orbits, Gloves of Glory, Hand of Glory, Charm of Brooching)
Charm of brooching does not creep power at all since it is a reprint, and since Shadowskin cloak is still in print, and there is a cloak in this set, someone new to URs could buy Shadowskin, charm of Brooching, and Cloak of the Elm and use them all.
Charm of Glory means there is no longer a meaningful sacrifice to be made equipping 3 rings - expect nearly every build capable of equipping this to equip this. Especially due to:
Arcane Earcuff. With a slot limit of 10 charms, there is no contention at the charm location, and charms can be expanded more than 3x their base amount. This does pair well with Charm of Brooching and Charm of glory, however, are you certain you want to allow trading 1 ear slot for 1 back slot and one ring slot?
Arcane Bracelets. Meaningful choice between expanding Charms and Iounstones. I like this one, though Arcane Earcuff likely means most will drop charm bracelets and replace with Arcane Bracelets and Arcane Earcuff, netting 2 IS to all builds.
Sets
Lucky Armor:
Has light and heavy armor options, and duplicates half of the Redoubt set bonus, which isn't ideal given available design space. I'm hoping next year this set gets lucky helm and lucky boots to extend the set for even more new players. Nothing else new to say here I haven't said before.
Arcane:
Set is amazing in power. Belt should probably become belt of focus. While that impacts Fighters / Barbarian / Paladin, that is probably OK given that Lucky Plate and Bracers of Reckless Fury exist in the set that won't be used by Wizard, druid, etc.
Slotless
10% of the set is slotless. I dislike slotless in general, so I still think both items should become slotted, especially considering the huge number of Ioun Stones and Charms that can now be equipped.
Skull moves psychic enabler to slotless - if I had bought The Dark Disciple shirt, I would probably be pretty annoyed. This will likely limit further sales of said shirt.
Key is unchanged and will yield 100+ healing per dungeon for the right group.
I recommending slotting both into charm or ioun stone slots.
Weapons
10% of set.
Rod of the Meek still seems awkward with the reference to the party card since the reference seems to only be there to act as a check against the Str limit. Can we come up with any other limiter with this? No Crits? Can't be used offhand?
Flaming Blade appears to be a viper strike fang reprint with less class restriction. Will this be FoB compatible?
Other
I like Cooks hat restriction at 3 IS. Great for newer player, but strong incentive to upgrade, just like the other +1 level URs
Ioun Stone Banshee Prism - should this reuse the same wording as the Blessed Tempest Gloves for consistancy?
Ring of the Drake - more or less combines 3 rings: Ring of Focus (without healing) + ring of frost + holly ring. That uses quite a bit of design space - perhaps the spell damage should be dropped and next year make a caster specific ring to go with the wizard gear?
Bracers of Reckless Fury - Glad the 2H trigger is back. For long term players (both old current players and newbs planning long term purchases), this is probably always going to lose to slot expander wrist items.
Should Pants of the Panther be +4 dex? +3 seems like a minor upgrade over Blessed Pants of the Hare, but I don't feel strongly here. Fatherbane is +6 dex with penalties as a reference point.