I wanted to go into detail about priest vs shaman and why the matchup needs to be addressed in a way.
First of all let me say that altough I am not a legendary player, I've been around rank 4-5 in 3 seasons as priest and play the priest class mainly.
When you go to http://hearthstats.net/reports/mar/index.html you will also see that in the Priest vs Shaman matchup the Shaman has more than a 60% winrate or to make it appear more drastically. Priest only has a 38% chance to win.
Now why is that?
- Comparing the two hero powers you will see that the shaman hero power actively establishes board control while the priest one strengthens existing board control. This means if the shaman has board control already, the priest hero power is -very- weak while the shaman one can continue flooding the board.
- Comparing the removal abilities of the two classes a similiar thing can be noticed. The priest removals are all very reactive and limited with certain boundaries save for example holy fire. Shaman removals are very versatile. They can be used offensively and defensively and are not limited by high manacost, attack of a minion or similiar.
Coming back to the priest removal. Unless they have existing board presence, outside of holy nova they do not have any way to deal with totems. Other classes can do so by their hero power, weapons, tokens or in hunter's case UtH, "preventing" totem use. Priest can -only- remove those with his board clear. While same applies to warlocks their really strong hero power helps them a great deal.
Priests have a -very- weak early game to most of the times turn 3/4. In very unlucky cases turn 5. Sometimes you draw a powerful cleric/blademaster/pyro combo but that's a really rare occasion as it requires a big combo in your opening hand. Shamans tend to establish board control very early with argent squires, totems and unbound+feral spirit combos. This is the point where priest is now behind. Looking at the above mentioned points, we are now behind in hero power, removal and with our minions.
Priests tend to play very strong minions exclusively such as yetis, circle+blademasters and stronger creatures so they normally stabilize somewhat in the lategame which evens out the game, however having to constantly put up with removing shaman totems as a priest greatly reduces the potential of those minions. (Personally I run alchemists in my deck, they are great vs zoo. They take out shieldbearers, mirror images and many more things. Especially flametongue and manatide totems are the best targets for them and I consider them to be anti-shaman cards.)
Shamans establish boardcontrol early with above mentioned cards. While doing so and the transition into the lategame happens, the shaman easily removes big minions such as yetis or circle+blademasters and lower-cost legendaries such as sylvanas/cairne, relatively easily while spending little to no mana. During that the priest takes tremendous amount of damage and due to how much value shaman cards have (flametongue, rockbiter, lightning bolt, feral spirit, fire elemental) are some cards that come to mind. It is almost impossible to come back and win the game.
There is games where I topdeck every turn and basicly happen to have the best priest plays possible such as circle+blademaster with coin or turn 6 cabal on a manatide/feral spirit. The perfect manacurve and draws, yet a shaman still wins the game because their answers are cheap, allowing them to hold board control long enough for their superior hero power to retake the game. Future threats are easily removed via earth shock or hex, even if you happen to bait some removals.
Now my point is not that shamans are OP or that priests are useless, altough they are without a doubt in a weak state. I mainly wanted to point out that the matchup itself is the most unbalanced matchup in the game. While warlock has an even higher winrate percentage vs priests, their decks "greatly" vary(zoo, murlocs, handlock) while most shaman decks are -very- similiar just like most priest decks.
I have not came up with a solution in the thread and we have yet to see what naxxrammas brings but I merely wanted to bring up the discussion altough there are not many shaman/priests players so not many people will have an insight on that matchup.