Make unique additions to the game:
[…]possibly Workshop.
Really? There are Ironworks, Armory, (Horn of Plenty).
Moat is new, but every attack can be blocked or at least weakened by other reactions.
Chapel is already redone with Forge and Count can serve as trasher as well, also there is Steward, Ambassador, Remake.
Cellar has Warehouse.
Village has brother(s) in every expansion, especially Farming Village and Fortress. I think people would wonder why village was not released earlier.
Chancellor: There is Scavenger, and Scavenger is so much better.
Woodcutter: Goons and Nomad Camp
Workshop: as mentioned above Ironworks, Armory, Horn of Plenty.
Bureaucrat: Jack, Fortune Teller, Rabble, Ghost Ship combined. New enough, though.
Moneylender: Spice Merchant. New enough, though.
Gardens: New.
Militia: Ghost Ship, Goons(!), Margrave, Followers, Mercenary. There are already many discard attacks.
Remodel: Butcher was released half a year ago, come up with new ideas!
Spy: Why is that so much weaker than Scrying Pool?
Throne Room: A smaller KC, Procession.
Feast: New enough. (Well, there is Altar, but you will rather open Feast to minimize shuffle luck).
Smithy: Torturer, Wharf, Rabble, Margrave, Catacombs, Journeyman, Envoy.
Thief: Noble Brigand and Pirate Ship.
Council Room: Governor's draw, Hunting Grounds. Still new enough, I think.
Festival: Squire and Fishing Village come into my mind. However, nothing too similar was released so far.
Market: cantrip buy like Market Square, Peddler variant.
Library: There is Watchtower.
Lab: Alchemist, Hunting Party, Stables.
Mine: There is taxman. Still, they play differently.
Witch: There are Junkers in every Expansion, and this one might be incorporated in an Engine nicely.
Adventurer: Venture. It should cost $5.
I would preview Gardens, Witch, Mine, Moneylender, Chapel.
Overall, people would wonder why they are pushed back to BM.