For me this is the Harbinger card from Dominion 2nd Edition. We played it not strictly following the from top to bottom. So you could look through your discard and then immediately draw it with the same card. It was super broken.
Or playing Milita but you always have to discard 2 cards, even if you are already at 3 or less. It was supid.
We love Clank! After dominion, our first modern euro (not counting settlers of catan) we got Clank and loved it. The majority of games we play are only my gf and I and while clank does work as a 2-player, its much better with 3 or more. Thus, it does not see the table often as other games.
However, we got Clank Catacombs soon as it came out and loved it. Works better as a two player too, because the routes are not so predictable. We had some games with super easy dungeon escape routes and others where almost everyone died trying to escape. I love that aspect of the game.
There are also a lot of cards that make +clank and this makes playing much more dangerous. I like that since dying in original clank was rather rare. Dying below the green line happened maybe once or twice in al the games we played of the original in 5 years.
Catacombs is borrowing some aspects of legacy and I think it really works well.