I thought what eHalcyon was suggesting (though maybe I'm wrong since no one else seems to have thought this) was to have a card that added a game-ending condition because it opens up some new possibilities for that card.
I meant a general rule addition, not one attached to a specific card. The intent is to open up design possibilities that are too problematic with the official rules. My example is +VP, which inherently has the potential problem of stagnant unending games. Having a game end condition tied to VP tokens would alleviate that. Yes, this specific rule would do nothing in games without a VP token card, but I think it would be valuable both to avoid the extra text on multiple cards that would benefit from it as well as to retroactively fix those rare broken cases with Bishop/Fortress and Monument.
In my experience Goons lead most often to a lot of VPs, after Fortress and Monument. Monument only leads to a lot if there is TR or KC on the board and as you already pointed out, Bishop is only abusive in combination with Fortress.
So we have two rare combos (which are IMO still interesting to play) plus the Goons thingy (which is IMO not but that is a problem of the card being overpowered). Hardly enough to warrant a VP token cap.
So, the point is to open up
new design space. The existing +VP cards certainly don't warrant this rule addition, since they were designed to work
without the rule. Bishop needs to trash cards so it naturally leads to a game end anyway; the problem only really comes up with Fortress. Monument is rarer because it only really comes up with KC-Monument AND strong trashing, already rare. Even in that situation, Monument produces enough coin that you'll usually buy a Province or Colony anyway. Goons is the
least problematic of the bunch, because you only get +VP from it by pushing the game to an end.
But with a new game end condition tied to number of VP tokens, it would (hopefully) allow things that would be bad design with the official rules.
I'm not particularly excited about cantrip +VP. It's not a design space I want to explored so badly that I would introduce a new win condition. Also, keeping track of the VP tokens the whole time would be fiddly.
That was just an example. What got me thinking about this was the lengthy discussion on Labyrinth in
this thread. It applies equally to pretty much any +VP fan card.
I've had at least 1 great game with Goons where both scores were well over 100, and there were a lot of good tactics involved in making sure you were the one to be able to pile out with the lead. The 100 vp suggestion would have stopped that from being a great game.
As I said, the 100 was just an arbitrary number. It could as well be 500 or 1000.
Bonus points for completing some set mission. Such at x points if you have no Golds at the end of the game.
Fine, but not at all what I'm asking about.
Yeah, I just for some reason thought he was talking about a new rule in general; nevermind.
No, you were right the first time. I'll try to clarify the general question:
There are some aspects of (fan) card design that most of us now take for granted. For example, non-terminal +VP is usually a bad idea because it can lead to a stagnant game state. My assertion is that this could be fixed by adding a new general rule, i.e. a game end condition tied to VP tokens.
Are there other problems with my idea that I haven't seen?
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.