A mid-to-late-game card that isn't dead when drawn on turn 1 or 2. Trades one health from Sunwalker for an immediate benefit before you even play the card. Synergizes with buffs, flood strategies, and Quartermaster-type cards. Flavorwise: Alonsus Faol, as a high-ranking member of the Silver Hand, sends reinforcements before joining the fight himself.
For the pace that hunters can draw through their decks, this could push out a lot of secrets in one turn. Quite a gamble without excessive card draw, so it'd only really see use in the cycling decks (like quest hunter).
A new take on Priest's "Steal a card from opponent's deck" effect. Here both players know what each other has drawn, leading to an interesting strategic mind game. The card advantage here is significant if you actually get all three cards, but you never know when or if you'll see them. I am assuming that drawing a Lost Page off of a Lost Page would just negate that card draw and go on to the next card - you'd only steal "real" cards.
Edit: Just realized that the second sentence could be misinterpreted. It should read "both players draw the top card of your opponent's deck."
Flavour: "I have changed my mind, I'll go with plan B"
More love for discard warlock and quest warlock. When you discard your hand by by play this card, you gain the same total random copy of cards from your deck, excluding this card (Change the Plan). But if you draw this card and discard your hand you gain the same total random copy of cards from your deck inculding this card (Change the Plan).
+ The good thing is, you can change your hand without drain out fatigue
- The bad thing is, you draw this when you have good hand and ruin your plan, thats why its called "Change the Plan".
So why does this card need to be "When you draw this..." and not just a Battlecry-minion with the same effect? Simple. If it was a Battlecry-minion that read: "Battlecry: Look at 3 minions with card text. Choose one and gain its effect.", you could end up with a lot of... yeah, other Battlecry-minions as the choices. Unfortunately, that wouldn't trigger the given Battlecry, thus this card would just be a 6 mana 5/5.