SCOUT IS THE WORST CARD IN DOMINION.
That's right, the oft-made-fun-of, oft-jokingly-called-overpowered, and oft-joked-about card Scout is actually the worst card in Dominion. There are a few reasons:
1) In absence of hybrid victory cards, Scout does nothing for your current turn.
Actually, it actively hurts your current turn. When you play it, you are left with 4 cards in hand besides all the useless victory cards you may or may not draw with it. It gives no monetary bonus, no extra even-possibly-good cards, nada. Now, you might say, "Tactician does nothing for your current turn either." That's true, however, through multiple games, it has been proven that one amazing turn is better (most of the time) than two mediocre turns. And, you can't discard any of the other bad cards with scout like curses or coppers. With Cartographer, it still does almost nothing for the current turn (except it's a cantrip so it doesn't hurt), you can discard curses, coppers, and victory cards. Scout just takes those useless victory cards into your hand.
2) When scout is at its best, it's too late to spend $4 on it.
In the mid-game, in a good engine with even a little bit of trashing, scout does nothing except rearrange the top four cards of your deck, because there are no victory cards in your deck at all. And when your deck is bloated with victory cards, enough to make scout useful-ish, it's too late to spend $4 on a card that you'll probably only see once or maybe even not at all. You'd be better off spending that $4 on a Silver that might help you reach a province later, or even an estate.
3) Even with hybrid victory cards, Scout isn't worth the $4 you spend on it.
It would be much more useful to spend that $4 on a Silver or separate engine piece. And the kingdoms where Scout is in the kingdom with Great Hall/Nobles/Harem/Island, and the Scout/Hybrid Victory engine is the best strategy, and there isn't a better engine piece at $4, are very rare.
"What about the other bad cards, mail-mi?"
All of them have better uses than scout.
Thief--Very effective against chapeled or heavily trashed down BM decks, and very useful in 4 player
Transmute--Can be useful if you miss that $3P for a Familiar on your second shuffle.
Duchess--It's a free terminal silver. Can always be useful in the late game.
Pirate Ship--Robz may disagree, but Pirate Ship has its uses. Check the "Robz vs. Pirate Ship" thread for a couple of examples.
Scout is the worst card in dominion. Period.