Catching up on commenting on these....
Knight
Action 6
+2 Cards
+2 Actions
+2 Buys
+$2
Discard two cards
I suspect this is substantially overpowered. Essentially, this is Festival + 1 Buy + Warehouse-style cycling of 2 cards. The second +Buy is less useful than first +Buy, so I can't see that alone as being worth an increase to $6. However, the Warehousing is, I feel, much too strong to warrant a price increase of only $1, particularly since this effect is on a non-terminal, thereby allowing you to use any actions you draw. This is a clear $7 minimum to me, and I suspect that actually it's an $8 or $9 card.
One way to look at it is that you'd basically
always want it in preference to Gold. It guarantees +$2, and it would be extraordinarily unlikely you couldn't gain at
least another $1 with a 2-card cycle. More often, you'll gain more than $1 from the cycle
and very possibly improve the actions you can play afterwards.
In other words, it's preferable to a Gold
even without considering the second +Action and the second +Buy that Knight also gives you. This is why I'm afraid it would be overpowered even at $7. I think this is probably an $8 or $9 card.
Two further comparisons are possibly very apt here. Both of them are Grand Market. Recall that in the Secret History of the Prosperity Cards, Grand Market began as "+1 Card, +1 Action, +$2" and cost $7. It changed to the form it's in now not because the card wasn't balanced at that price but because playtesters complained that something called a Market should offer a +Buy. As a result of that, it morphed into the card it is today.
Well, hey -- if +1 Card, +1 Action, +$2 is worth $7, then surely Knight is a more powerful card by comparison. Knight doesn't get the 1-Card hand-size benefit, but in exchange it gets cycling AND an Action AND TWO extra Buys. The cycling benefit is probably roughly equivalent to +1 Card, in terms of power level. And the Action and the Buys, together, are probably roughly equivalent to +1 Card in terms of power level, though that's pushing it. But with all of those benefits, Knight is clearly superior to this $7 version of Grand Market. We're looking at $8 or $9.
Now compare to the final version of Grand Market. Without the Copper restriction, it would have to cost somewhere in the neighborhood of $7.5. Again, this version has the 1-Card hand-size benefit that Knight doesn't have, but Knight compensates with cycling and an extra action and an extra buy. As with the other version of Grand Market, this is WAY too much compensation for the lack of a single +Card.
Another way to look at it is that Grand Market, when you can get it, is almost always preferable to Gold. There are times when it isn't, but usually it is. However, not only is Knight practically ALWAYS preferable to Gold, it doesn't have the very important Copper restriction that Grand Market DOES have. So basically you have a card that is more powerful than Grand Market AND easier to buy, but at the exact same price.
I like the idea of the card, but I just don't think it can work. Maaaaybe if you put the discards first, it would be okay at $7.
Sack
Action-Attack 6
Every other player reveals cards from the top of their deck until they reveal a victory card. They trash that card, which you then gain. The rest of the revealed cards are discarded.
Trash your hand.
Trash this card.
Pretty impossible to predict how this will play on average. But one problem is that there
isn't an average. Either it does nothing, because you can't bring yourself to trash your hand, or it's decisive, because trashing your hand is easy when it may very well mean certain victory. In multiplayer, the VP shift could be astronomical. In fact, unless you defend against it by sucking up Estates and Duchies, to minimize Sack's chances of hitting your Provinces and Colonies, it probably WILL be a huge and decisive VP shift. And cluttering your hand up with Estates and Duchies, besides making the game kind of tedious, still might not work.
All in all, there are way too many points at which shuffle luck can determine the outcome of the game.
Emperor
Victory 6
Worth 1 VP plus 1 VP for every 3 victory cards in your deck
Originally I had this as just 1 VP for every to Victory cards, no 1 VP baseline. But I realized that that would more or less just supersede provinces, so I weakened it a touch. Now I think it's interesting.
play2draw sums up my feelings here. It's probably balanced, but I don't know that it changes the game enough to be interesting. Fairgrounds admittedly sets the standard high for fun, game-changing VP cards, so Emperor isn't bad if it's not as interesting as that. But is it as interesting as Duke? Not sure.
One thing about the $6 price point is that it makes it hard to use in rush strategies. But it might be tough to build a long-term strategy around, too, since you'd want a lot of green cards to maximize the value of your Emperors, and green-heavy decks don't necessarily do very well in the long term.
Viceroy
Action-Victory 6
The opponent to your left picks either action, treasure, or victory. Gain a card of the named type.
Worth 2 VP
Probably I could change this to: "The opponent to your left picks a type. Gain a card that doesn't have the named type" and it would be better and more interesting. 6 cost on a gainer is awfully high.[/b]
I like this idea, but I suspect it will need some tweaking. You're right that $6 on a gainer is high, but you can basically guarantee a power card every time you use it. Plus, it's got that 2 VP, which makes it useful anyhow. This certainly feels more powerful than Harem and Nobles, which also offer 2 VP at the same price.
Some observations:
(1) Nobody will ever name Victory, because you can just pick up a Province or Colony with it. I suppose your opponent might be okay with letting you snag a Province if you get a lucky $6 on turns 3-4 and play a Viceroy on the very next shuffle. But even that would be quite a dubious move. Yet even in this case, the player has an out, because if it's truly too early for a Province, he can gain another Viceroy instead, putting him up another 2 VP while not burdening his deck with an otherwise useless card.
(2) You basically always get a power card, no matter what the kingdom. If Platinum isn't available, there is always Gold. And if you are to gain an Action card, you can always gain another Viceroy, even if everything else in the kingdom is junk. But probably everything else *isn't* junk, so you will usually have better choices.
(3) Against a Viceroy player, therefore, what can you really do to limit his dominance? If there are any action-based engines possible OR any power cards like Grand Market or King's Court, you're probably hosed no matter what type you name. If there isn't, probably you name Action early and Treasure late, but that will still be potent. And if Harem is on the table, you probably have no choice but to compete for Viceroys.
(4) So how do you play a Viceroy mirror match? Maybe by naming Treasure, so the other player can't get more Viceroys? But then you're enabling him to buy them outright, or, perhaps better yet, leap straight to Provinces via an accelerated Big Money strategy (since a Viceroy turn might easily net you two Golds, or a Gold and a Silver).
I like the gameplay possibilities this line of thinking suggests, but it does seem too potent. Your alternate wording is probably much stronger still, despite weakening the player's ability to accrue Viceroys or other dual-type cards. But probably what this card needs is to be put on some kind of leash. All existing gainers have a cost cap except Jester, which instead limits your selection. I don't think limiting by type is enough of a selection limitation, and I can't think of a good cost limitation that would both solve the problem AND keep the card interesting. So it's a tough problem, but I think the idea is interesting enough to invest the effort into.
Blacksmith
Action 6
+1Buy
While Blacksmith is in play, every treasure card produces an additional $1 when it is played.
A bit like Bank, but different enough that I think this could be fun. Requiring an action in exchange for the +Buy seems like a good trade.
The effect of multiple Blacksmiths is tough to compare with multiple Banks. Multiple Blacksmiths are harder to play, and while each Blacksmith will count every treasure card (not the case for multiple Banks), the fact that Blacksmith isn't a Treasure card means that having multiple Blacksmiths in hand may, in turn, mean fewer Treasure cards to earn from.
I think this is probably a balanced card and more interesting and distinct from Bank than it at first seems. You might still have to go to $7, especially with the +Buy there, but it's a tough call.