Oracle seems like a real dog of a card, like serious contender for worst $3 bad. You get the drawing power of Moat (but not the defense!) coupled with a terminal Spy-type attack that is arguably not even better than Spy. Because your opponent can order the cards, it's not even really useful for setting up other types of attacks that care about the top card like Jester, Saboteur or Swindler. Any other candidates for worst card in the expansion?
edit: Okay, you get slightly better drawing power than Moat as you have the option of pitching total garbage. Still seems like this isn't going to be worth it very often.
Oracle ain't
that bad. Looking at what you draw beforehand makes a big difference. I could see it being at least as disruptive to your opponent and as helpful to you as, say, Fortune Teller, which is pretty weak but not worst $3 weak.
At first blush, I was tempted to call Jack of All Trades pretty bad, but now that people have brought out convincing evidence that it's a great BM enabler, I will upgrade it to annoying instead. (Part of why I really dislike Envoy is that its presence often forces fast and boring BM matches, and if Jack is as good as people say it is, I'll end up disliking it just as much for the same reason.)
I stand by my assessment of Mandarin as pretty bad, its treasure-giving powers compare to the mediocre Harvest and Merchant Ship, its "return cards to deck" powers will be situationally useful but usually a drag- I can't imagine them being useful more often, or more useful, than something like Outpost. I could see Mandarin and possibly Cache too being considered for Worst $5 lists. Cache is probably better than Contraband in general, but those Coppers have to be a pretty big downside in many games.
Duchess kinda sucks, and alas there's not much more to say about her. My sense is that Fool's Gold is also a lot weaker than most people think, there are occasional situations where it can be good but not that often.
You know what card I bet is actually real bad? Develop. If you use it on a Copper, congrats that's a terminal action to trash one card. Use it on an Estate, okay top-decking a Silver is nice but that's the Bureaucrat problem all over. It's just so slow as an early trasher, and so so easy to screw up when you try to develop bigger cards, that after a couple aborted attempts at using it I've just let it set there the part few games and not regretted that decision one bit. I would seriously consider Develop for a spot on the Worst $3s list.
A few of the $4s look not so hot either: Silk Road feels like a worse Gardens most of the time, and for all that it's supposed to be a strictly better Thief, I can't imagine Noble Brigand actually being that good. Nomad Camp seems like it's unexciting and a worse-than-expected opener, but I think it's actually a great late-game buy if you've got an engine that can inconsistently kick off to lots of cash- buy the Camp on one of your off turns after you've built the deck, and have it when you need that second buy with your $16.
...
Man, that's a lot of cards I don't like all that much. They're not all like that (though there are a few others that I bet are being way overbought right now)- Border Village, Margrave, and Cartographer all make me very happy, and Stables seems good enough to get even me to start buying Silver again.