Just had an idea for a card...
Swamp
$2 - Victory
Worth 6 VP
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When you gain this, if you have taken more than 2 turns (including this turn), trash this.
Basically, it's a victory card that is worth more points than it should be, but with the huge drawback that you can only get it as part of your opening. Costs $2 so that anyone could open Swamp/Swamp if they wanted to. Named Swamp because it's a land that slows you down.
Not sure at all about the VP... 6 sounds possibly too strong, like opening double-Swamp will too often be good. 4 sounds almost definitely too weak. While 5 just seems like a weird VP value for a card to have, I dunno.
It might be too simple of a decision; Big Money = get Swamp, Engine = avoid Swamp. Weak Engine = 1 Swamp but not 2. Maybe. I mean, if you open double-Swamp, and your opponent doesn't, then you only need 3 Provinces to his 5 to tie.
There's technically a tracking issue in that the number of turns you have taken is not recorded information IRL. Obviously in practice I think people will know if it's still their opening, but as we've seen in the puzzles, openings can be completely crazy with Noble Brigand and other stuff.