With a new expansion coming out, I inventoried my Classic collection to see how far behind I am since the holes will only be harder to fill with more cards available. If I only had one copy of an epic/rare, I added that to my tally, too.
Missing Classic Cards
Druid: 2 Rare, 2 Epic, 1 Legendary
Hunter: 1 Rare, 2 Epic, 1 Legendary
Mage: 2 Rare, 3 Epic, 1 Legendary
Paladin: 3 Rare, 5 Epic, 1 Legendary (easy to see why this is my worst class)
Priest: 4 Epic, 1 Legendary
Rogue: 1 Rare, 3 Epic, 1 Legendary
Shaman: 3 Epic, 1 Legendary
Warlock: 1 Rare, 4 Epic, 1 Legendary
Warrior: 1 Rare, 1 Epic (eat to see why this is my best class)
Neutral: 2 Commons*, 18 Rares, 12 Epics, 20 Legendaries
*I somehow have zero Windfury Harpies, wtf? I have 2 copies of every other common card in the set, though.