Another aspect of Oracle is that it can mess with your opponent's shuffle timing.
While it's hard to say whether it's good or bad to force your opponent to reshuffle as you don't always know what cards he has in his hand (maybe 3 Estates and 2 Coppers), it is a feature of the card.
Thief, Noble Brigand, Tribute and Pirate Ship also dig two cards deep into your opponent's deck.
Completely separate from shuffle timing (or filtering, or drawing) is Oracle's ability to peer two cards deep into your opponents' decks. No other card allows that. In the presence of villages, this allows priming targets for certain attacks or a favorable Tribute. The reordering of the top two cards does nothing to stop the attacks from Thief, Noble Brigand, or Pirate Ship. And depending on the revealed cards, it may also ensure good hits for Saboteur, Swindler, or Jester. With extra actions, Oracle can be better than two consecutive Spies in setting up decks for attack.
