Crossposted from the other prediction thread:
Feodum: Ew. Ew ew ew ew ew ew. I really don't like that this card exists in this form at ALL. I mean, sure of course there has to be a Treasure-counting alt VP card, but Silver-only still doesn't sit right with me even after Donald's explanation. He excluded Copper because it would be too similar to Gardens, but Silk Road already plays very similar to Gardens anyway, so since when is that a disqualifying factor? And I don't see why Kingdom Treasures need to be excluded, you don't always want them. (Heck, sometimes I don't want Gold.)
As for the pinata ability, it's a double-edged sword. Trashing Feodum for benefit for the Silvers and not actually going Feodum is, I suspect, going to be pretty slow and not necessarily better than just buying Silver to begin with. C.f. Treasure Map, which is a bad card that gets you four golds when you line it up: and lining up Feodum/Trasher is easier, but the immediate benefits are far lower, too. If you trash Feodum to get Silvers to feed your other Feodums, that's a tough tradeoff too. What it
does do, however, and I am frustrated just thinking about it, is throw a kick in the teeth of denial strategies. For example, Bishop is a great Gardens counter, but if you're going for a slim Bishop deck you may not be as able to just blithely buy and trash Feodums.
Obviously, it's going to be great with Silver-gainers like B-crat and Explorer; I suspect a Jack deck will still just want to go Province anyway, though I could see it possibly grabbing Feodums over Duchy in the endgame. In general this is a card that is going to be ill-suited to rush strategies, and instead feature mostly as cheap Duchies in silver-flood decks that get most of their points from Province. I can also predict with confidence that I'm going to hate this card.
Cultist: I don't see how this can be anything but super strong. While Ruins don't hurt nearly as much as Curse, a self-chainable junk-giving card that can find itself, and then gives you a bonus late-game when the Ruins are depleted, is going to dominate games nearly as much as Witch. (This is because the fact Curse being a dead card is usually even more harmful than the -1 VP.) I suspect chaining Cultists is going to be not very common in practice, because if all the players go Cultist like they probably should your deck is going to get junked up and it'll be hard to line them up often. The when-trash bonus, however, is going to be really nice in games with trashing, which balances the fact that the presence of trashing is obviously going to take the sting off of Ruins a bit when it exists.
Ruined Market: Yeah, as mentioned by others this is actually probably one of the more useful Ruins. These things may not be as bad as Curse, but I sure as heck won't want a deck full of them.