According to the little research I made, the Joker was later represented as a clown because people tended to confuse it with "The Fool" from tarot cards. The 'Ace' card represented the people who served the king, who later would gain power and remove the nobility (the card from the king). That's why it's higher than the King's card.
Also, they made the cards to be seen from both sides so people didn't know or guess which cards the other had when they turned around (because we usually do this when a picture is upside down).
