The card as submitted was
#19 (tie) - Burnt Offering by Mecherath with 5 points (Theda)
$5 - Action
+1 Buy
+$1
+1 VP
Trash a card from your hand. If it is an...
Action card, play it three times.
Treasure card, +$ equal to its cost.
Victory card, +VP equal to half its cost in coins, rounded down.
When I made it, it was trying to do too much. Since it cost more than both Bishop and Salvager, I wanted to make sure it was strictly better than each, which is how the Buy, $1, and 1VP got added on. That made the card too busy, and as at least one person said, trashing a card you're done with anyway, like a curser, makes the KC benefit extremely good.
I'm thinking of a version where the card is cheaper, but also has toned down abilities. It would be:
Burnt Offering
$3 - Action
Trash a card from your hand. If it is an...
Action card, instead play it twice, then trash it.
Treasure card, +$ equal to its cost.
Victory card, +VP equal to half its cost in coins, rounded down.
Knock the action down to Throne Room, and remove the extra stuff. It imitates 3 different 4-cost cards but is weaker than any of them, except when dealing with multi-type cards. It's missing the +Buy of Salvager, the +$1/VP of Bishop (though also its benefit to your opponents), and the ability to keep the card from Throne room. It also can't do anything with Curses.
You can still make a Golden Deck out of it, though you need Gold, Gold, Silver to do it, and wouldn't be able to trash a gold on the final turn to keep the last Province.
Not sure if these changes would have made it do better in the challenge, but I think the sheer number of things it was doing made it harder to judge. Thoughts?