Well, in the meantime, here is a novel I wrote about developing Danse Macabre. A card which I also voted for! (Along with Bargain, Garderobe, Incendiarist, and Stronghold.)
After making a few cards that went mostly unremarked upon, I'm very happy to have a card provoke some conversation, even though not everyone liked it. Thanks for the attention, it was incredibly rewarding!
I knew I wanted to do a card that was kind of morbid, like Rats and Knights. So, first I thought of the name.
The second thing I thought of was a card that trashed on buy, an idea I really dug. Like Grand Market, activated City, Prizes, Hermit and Madman, this would be a card you couldn't get the usual way. Who doesn't love that? And because Dark Ages has Rogue and Graverobber in addition to the usual amount of gainers, it fits nicely into the set. There's more likely to be a path to Danse Macabre, if you really want it.
But I didn't want Macabre to be a dead card when there's no way of gaining it. So, an on-trash benefit seemed like it would fit the card and the set in a satisfying way. Just had to come up with a nice on-trash benefit.
For a while, Macabre cost 6 and could top-deck an action. At first, it's on-trash could top-deck ANY action. Hey, why not? How often would it appear with King's Court anyway. But, I dunno. With Baker in the kingdom, you could get a second-turn Forge paired with your three starting Estates, and that seemed like way too much, even for me. Then it could just top-deck cheaper actions, and that seemed ok, if a little derivative of Border Village. But, it had this really boring interaction with Graverobber, where you'd buy Danse Macabre, topdeck Graverobber, then use Graverobber to topdeck Danse Macabre. Kind of programmatic. And Graverobber should be one of the more fun interactions, so I ditched that idea.
Next, Macabre cost 4 and could get two cheaper cards. But that seemed like it would often be too strong. So, I thought, what about a cheaper card and an even-still-cheaper card? That would be good sometimes, and suck sometimes. Again, it fits with the set, because, hardy-har, Poor House-Hamlet. And though the effect would often suck when there's no $2s, it would never be COMPLETELY irrelevant, because in pretty much any kingdom, there's a plausible game state where you would want to buy Estate on 4, and now you can get a Silver with it.
It was hard to come up with a simple way to describe a second, even-cheaper card. Finally, I thought of "two cards of different costs" and decided, OK, that doesn't exactly mean what I want it to mean, but it's simple. Then I realized, actually it means exactly what I want it to mean! A card and a cheaper card = two cards of different cost. That epiphany was a the high point of my card-designing hobby so far.
And then finally I had to decide what the card actually did. But, I couldn't think of anything, so I gave up. I started working on this other card that plays an action for no effect, then gets a cool benefit. Then I decided to just put that onto Danse Macabre.
Problems with the card
The biggest problem with the card is the on-trash effect. I love it, but it's really pile-draining. If there's a good $2-$3 combo, like Hamlet-Menagerie, the game will end as soon as it starts. I'd prefer not to change the benefit, but the only solution I really came up with is limiting the number of Macabres to 8.
Some people are vexed by the "play an action for no effect." That's understandable, as it's the only thing in the game like that. But, that's also what makes the card cool. Playing an action for no effect is, as these things go, not ALL that confusing. It's easy to track. Yeah, it creates rules questions, but all of them have clear answers. An action played this way plays as if it has no text in its box. It triggers Conspirator, Horn of Plenty, Urchin, and Horse Traders, because it still has a card-type and a name. But it does nothing else. It has no "while-in-play effects." Durations played this way leave play during clean-up, as Tactician does when you play it with no cards in hand, (that is, "for no effect.")
EDIT: I see now that the technical Dominion term for the text in the box is "abilities" not "effects." It would be clearer wording to use the correct term on the card itself.
I prefer "play an action for no effect" to "set-aside an action now and discard it during clean-up." Though they have similar effects, the first phrasing is simpler. So that's my marginal preference. Of course, discarding an action is simpler still, but it's not as harsh a penalty, and so the benefit can't be as cool. That's my least favorite way of doing the card.
Then third, there's the benefit. +4 Cards and +1 Action is pretty strong. Is it too strong? Well, that's the benefit of Village-Smithy. It's also only one more +card than Stables, which discards dumb Coppers instead of wasting actions. But, at 4, Danse Macabre is cheaper than Stables. On the other hand, it's harder to get. But, with Ironworks, Talisman, Haggler, etc, it's not THAT hard. So, is the bonus too good?
Ironworks-Macabre I thought about a lot. It's really strong. It's different from Ironworks-Village-Smithy, because the Ironworks IS the Smithy. (Or the Village. Or it's an Ironworks!) If you open Ironworks-Silver and then just buy Ironworks and use Ironworks to gain Danse Macabre, by turn 7 you can draw your deck, buy a Province, and also gain more Macabres. You can do that 8 turns in a row, with luck. I think you probably are unlikely to have that optimum luck -- sometimes you'll have dead hands. And, hey, other combos can get all the Provinces by turn 14. (Right?)
But, the whole sequence feels like it might be programmatic and boring. I think the problem is, wasting an action is sad. Actions are fun. Drawing cards is a little less fun. I worry that +4 cards, +1 Action doesn't quite make up for wasting an action, in terms of enjoyability. I suspect the bonus is not so game-breakingly strong, even with Ironworks. But I wonder if it should be more interesting than "lots of cards."
Finally, some people don't want the card to have two lines. They just want one big mushy sentence. I don't get that at all. Lines are great.