Are there other problems with my idea that I haven't seen?
Well the obvious one is that different VP token cards can get tokens at a wildly different rate. A number that's a reasonable maximum for one such card might still lead to unreasonably long games with other such cards.
If the rule had been in place since the beginning (or since Prosperity), then cards could be designed with that maximum in mind.
I don't think the rate matters that much. I think "unreasonably long" is not really a problem compared to "unending". An easy example -- suppose two players both pursue Bishop-Fortress and they come out even. They end up gaining +VP at the same rate. If one player ever tries to proceed towards a game end by buying anything at all, they'll start to fall behind and the other player will be able to end it on a win instead. So they're both stuck playing the same turn over and over again until somebody resigns or somebody dies.
With a VP token end condition, this is avoided. Whoever reaches the "finish line" first wins, period. Even if it would be a long, long game to get there (depending on whether it's 100 or 1000 or whatever) the players could easily extrapolate -- Alice has the lead and they're gaining VP at the same rate, so of course Alice will win.
My intention is to choose a number that doesn't really impact the original cards much except in the extreme circumstances.
What other "closed" card design spaces could be opened up with a new general rule?
This latter question is difficult because it requires going back to look at old assumptions.
Nothing jumps to mind.
It's tough, which is why I'm asking other people if they have any ideas along these lines. The discussion is headed elsewhere though...
OK, how about this -- we take for granted that attacks should not simply prevent an opponent from having a turn ever again. The most common incarnation of this is a card that forces players to "discard X cards" with no other restrictions. In official games, this could happen from a pin -- something faust has
mentioned above.
What if the Event that faust proposed was just a rule of the game? If you start your turn with no cards in hand, the game immediately ends -- now the person who wants to pin would likely lose, since their deck wouldn't have any VP in it. Or it could be a minor mulligan rule -- if you start your turn with no cards in hand, immediately draw 3 cards.
Rules like this would severely nerf pin combos but also open up design space of cards that potentially take a player down to 0 cards, which could open up new design space for attacks based around this idea.
Goons is the least problematic of the bunch, because you only get +VP from it by pushing the game to an end.
Sure. But if you are concerned about players getting too many VPs from VP tokens and wanna cap it Goons is an obvious candidate which would warrant such a cap as among the three official card it is the one which on average leads to most VP tokens.
Does not mean that I think that the cap is necessary but if you introduced a cap you should be aware that among the three official VP token gaining cards it would weaken Goons on average the most (which IMO wouldn't be a big thing as Goons is overpowered).
I think you are wrong on that front for 2 reasons.
First, Goons games normally don't lead to close games where both players are consistently racking up points the whole time (though it
could happen). If there is no way to play multiples, Goons is an attack with some bonus VP in what is just a regular game. No problem there. But when you can play multiples, then it's an intricate game where both players build up engines as they try to find a way to pile out with the win. The scores stay relatively low (that is, relative to the final score) most of the way through until the last turn, where the winner piles out and uses all her extra +Buys on VP cards and Copper (which would have been anathema any time earlier), leading to a sudden explosion of points. The imposition of a game end tied to VP tokens would not impact this because players would not normally pass the ending threshold unless they were going to pile out anyway.
And that's the second reason Goons wouldn't be weakened - my proposal isn't merely a cap. It's a game end. That means that Goons would actually be
strengthened if the threshold were set too low, because it would just turn the game into a race to reach that line first.
Now if you wanna try out cantrip VP token gainers (personally I do not see much merit in that) you can do that (my uneducated guess is that a pure one would probably cost 5$) and you will soon see how much VP tokens such a card generated on average which would be the basis for a maximum value of VP tokens. Obviously in decks with non-terminal and terminal VP token gaining cards such a cap would make the latter weaker.
As others have said, I think it would make more sense to put the extra game ending trigger on the card. Only so much cantrip VP token gaining variants one can come up with.
Or if you wanna do non-terminal VP token gainers you simply nerf them directly instead of via a cap. Asper's Hospital comes to mind. After all the problem of a cap is that if a card is so strong that it will generate on average create such a huge load of VP tokens all players will go for it anyway and the only tricky decision is to balance how much of them you need in order to (nearly) reach the maximum of VP tokens.
As I said
earlier, the simple cantrip was just an example.
The card that got me thinking about this isn't even an action, and I think this rule would open up design space more. I also
explained why this would be better as a new rule as opposed to something tied to specific cards - it eats up physical card space and it would require multiple dividing lines for certain card concepts.
Here are some quick concepts that might work (after some tweaking) with a VP token end condition that probably wouldn't work without one. Let's say the end game condition is 200 tokens (and there would be 10VP denomination tokens for easier tracking, probably).
Passage
$5 - Action-Reaction
+2 Cards
+1 Action
Discard a card.
When you discard this other than during a Clean-up phase, you may reveal it. If you do, +2VP.
Since it is non-terminal and combos with other non-terminal cards like Warehouse, having the end condition is important. Putting it on the card would require two dividing lines though, ugh.
Land Surveyor
$2 - Action-Reaction
You may return a card from your hand to the Supply. If it is a Victory card, +VP equal to its cost in coins.
When you would gain a Victory card, you may reveal this from your hand. If you do, instead, +VP equal to its cost in coins.
This one is terminal! The concept is a card made for actively stalling the game. It clearly needs the rule to bring the game to an end. I don't think there would be room to put the rule on the card itself, but even if you could, it would be two lines again.
Merchant
$5 - Action
+2 Buys
Take 2 coin tokens.
In games using this, coin tokens are also VP tokens.
Another terminal. The rule is important this time not because of this card but because of what it does to other cards.
Landlord
$4 - Action
+2 Cards
Reveal your hand. +1VP per Victory card revealed.
Terminal, but dangerous with any sort of village. Double Tactician would be particularly threatening. Granted, this one could probably have the condition on the card itself, but I think this is enough examples to show that it would be worth having as a rule in the rulebook.
Village Savant
$4 - Action
+1 Card
+1 Action
+1 VP
You may return any number of VP tokens for +1 Action each.
Straight forward. Again, the rule could be on this card, but it's cleaner if it isn't.
Anyway, these probably aren't good cards as they are. They're just to illustrate the wide variety of cards that might work with a VP end condition in place.
