Transmute, Revised
Action, P
Trash a card from your hand.
If it is an…
Action card, gain a Duchy
Treasure card, gain an Action costing up to $4 more than it.
Victory card, gain a Gold
When you buy this, +1 Buy.
The two changes are: adding “When you buy this, +1 Buy” (so that it’s easier to buy), and gaining an Action costing up to $4 more than a trashed treasure (instead of gaining a Transmute). It can turn your Potion into a Prince!
I saw someone else propose “when you buy this, +1 Buy” to make Transmute easier to gain. It’s commonly recognized that Transmute turning Treasures into Transmutes is a key flaw in the card. I’ve seen multiple solutions to that, including “gain an action costing up to $4” or “gain an Action” - I chose something in between these power levels. It still doesn't seem like a strong card, but this version should have a reasonable probability to get bought even on boards where it is the only Potion-cost card.