So I was checking out the hero abilities (was looking on hearthstonepedia, let me know if that proves to be inaccurate) and it seems like some are clearly better than others.
Obviously we will have to see how the decks build etc but take a look for yourself:
Warrior Ability: Gain 2 Armor
Hunter Ability: Deal 2 damage to enemy Hero
Rogue Ability: Equip a dagger with 1 attack and 2 durability, or increase dagger's attack by 1
Mage Ability: Deal 1 damage to minion or enemy hero
Priest Ability: Heal a minion or hero for 2
Warlock Ability: Lose 2 life and draw a card
Druid Ability: Gain 1 armor and 1 attack
Paladin Ability: Summons a 1/1 Silver Hand Recruit
Shaman Ability: Summons one of the following (randomly):
1. Healing Stream Totem (0/2): at end of turn heal 1 for all friendly characters
2. Stoneclaw Totem (0/2): Taunt
3. Searing Totem (1/1): Battlecry - 1 damage
Now I dunno about you guys, and obviously it's a bit early to discuss balance and stuff (especially since we don't know exactly how the deck builds will differ from class to class) but a few of those just seem way better to me.
The warlock being able to sacrifice health in order to draw? Pretty amazing since "drawing out" is one of the main ways people lose cardgames.
The Paladin having a free summon regardless of what is in his hand? Pretty great as well.
Shaman is RNG but still has some great stuff there depending on what totem gets summoned.
By comparison things like 1 damage to minion or enemy or +2 armor seem pretty... tame.