Now that I have your attention, here are the facts for you and how everyone beats them.
1. Shaman 52.34%
2. Druid 51.96%
3. Warrior 50.92%
4. Paladin 50.89%
5. Hunter 50.32%
6. Rogue 50.15%
7. Warlock 49.97%
8. Mage 45.58%
9. Priest 45.20%
1. Rogue 53.44%
2. Mage 52.55%
3. Shaman 52.27%
4. Paladin 52.18%
5. Druid 48.39%
6. Warrior 47.56%
7. Hunter 46.05%
8. Warlock 43.71%
9. Priest 42.42%
Now you must be thinking, how? They buff Lightspawns, Lightwells etc to 20/20+ and completely own me!
Well heres a card you should have two of in all of your decks.
♦**Spellbreaker. Spellbreaker is a 4 drop 4/3 that silences. Not only does it make Lightspawns 0/1, but it counters a lot of other buff cards and can stop deathrattles from happening such as Harvest Golem, Sylvanas, Cairne, etc. It also dispels taunt and divine shield.
**Druid use two Keeper of the Grove
**Hunter use two Ironbeak Owls
--♦ Now lets assume they use two Divine Spirirts and an Inner Fire on one card. Your Spellbreaker officially made that a 4 for 1 trade, making your chance to win almost guaranteed.
--♦ Now you must think, I cant always draw these silences... well it goes the same for the priest too. He cant always draw Divine Spirits, Inner Fire, or Power Word: Shield either. However, every deck has some borderline removal cards such as Assasinate, Naturalize, Equality, Polymorph, Deadly Shot / Hunter's Mark, Hex, Execute, and Shadow Word: Death.
The absolute likelihood of you not drawing any of those 4 cards by the time they draw their four cards is very unlikely. Also when vsing a Priest do not ever mulligan a silence or a removal.
--♦ Even though I stated earlier that if you trade 4 for 1, some people have trouble with Mind Control.
If you put enough raw pressure on the priest and save a Removal spell, then drop something you know you ABSOLUTELY can destroy the next turn, you will be fine. Mind Control is 10 mana, meaning the Priest is going all in during this turn.
--♦ Regarding Thoughtsteal and Mindvision, these cards just set the Priest behind a turn, and are very likely to backfire. It's a gamble.
--♦ Avoiding the Power Words. Actually, a lot of the best cards in the game have 4 attack, just to list a few.... Chillwind Yeti, Argent Commander, Azure Drake, Dark Iron Dwarf, Cairne, Druid of the Claw, Kor'kron Elite, Twilight Drake, Sunwalker... The list goes on.
In reality you are not making your deck weak against any other by adding these cards, you're simply rounding out an efficient deck using these cards, and they counter Priest as well.
--♦Last of all, the biggest counter to a Priest is playing aggresive. If he plays Northshire Cleric on turn 1, thats GREAT for you. Just drop a 3/2 and kill it off fast. As long as you keep good tempo the Priest will never be able to keep up with the damage and will be forced to spend turns healing instead of using cards.