I would often pick Shimmering Tempest here, but the deck already has one, and I don't wish to fill it with weak 2-drops. Shroom Brewer is a good 4-drop and could potentially heal The Lich King or your hero against aggressive decks. I do want at least one card with a silencing effect, and Spellbreaker does just that while also being a decent 4-drop.
2. Shroom Brewer
3. Shimmering Tempest