Hearthpwn

Went from Rank 4 to Legend in the past two days. I consider this deck to be very powerful currently on NA.

Most typical matchups?

Here's what I have seen, from most popular to least, on NA:

1. LOTS of Mech Mages - Favored slightly, sometimes Control/Value/Secret Mage, pray their Unstable Portals RNG badly. Didn't see one freeze mage these past few days.
2. Hunter - Favored (Face or Mid-Range, usually face)
3. Druid - Even (Whoever gets the Wild Growth wins, usually), favored against Taunt Ramp, seen very very few ramp.
4. Warrior - Favored
5. Paladin - Slightly unfavored (I've been seeing a lot less of these lately).

Priest/Warlock I've barely seen any of, strangely enough I've not been seeing many oil rogues (I would figure this would be more popular), but the ones I have seen usually give me a good beating. A few mech shamans here and there, I believe we are unfavored in this, but not enough data to verify.

Only one Force of Nature?

For consistency, it's better to have one than two. You only need one to combo down your opponent, and having a second one typically makes it stay as a dead card in your hand. There are times when a 2nd FoN (Force of Nature) is good removal, but usually it's too expensive and you're already far behind if you have to do this.

Then why two Savage Roar?

Because typically one can be used to help with removal, and it's a low mana cost to boot, it also helps to guarantee then when you do draw the FoN, then savage roar will be there too. There's also the good old rare chance of FoN + Savage + Innervate + Savage. There's also times that it can act as a finisher on its own with your board and not needing FoN.

No Black Knight?

I found this card to be a bit too slow + not enough practical use rather than it being a 6 mana 4/5, it's amazing vs Handlocks and Ramp Druids, but there are very few of these around currently. You're worried more about Mech mage, and killing that Annoy-o-tron for 6 mana generally isn't that fantastic.

Why Harrison?

I find the benefits of it to be much too valuable if used when needed, it can completely disrupt the opponent's plan (there's no better feeling than triggering a hunter trap to give their bow +1 charge then using Harrison). Even if you are against a class that doesn't use weapons, it can still be dropped as a 5/4 when mana allows for it.

Why Dr. Boom?

I've been debating whether to keep this card or not, but I find it to be an excellent tempo play usually. Yes it fails to BGH, but with good RNG the boom bots can sometimes make up for it. It also combos quite well with Savage Roar. Mech mages and Hunters do not run BGH either. An alternative is Piloted Sky Golem.

Why no Sneeds/Kel'Thuzad/Foe Reaper/etc.etc.

Too slow in my opinion, you generally want to play things that have an immediate impact. Cenarius is a great example of this. Ragnaros is a possibility if you want to fill that 8 mana slot, and I've seen a couple of druids trying this, but I can't fully comment on it.

Why Sludge Belchers?

To help against aggro, I've found that two Druid of the Claw is really not enough taunts. Some people use 2x Spectral Knights or 2x Azure Drakes, if all I was facing were control decks, I would do the same. Right now there's too many Mech Mages and Hunters.

1 Azure Drake?

This card can be substituted with your preference. MC tech is a viable alternative, Spectral Knight, Kezan Mystic, Ragnaros, etc etc. Even Thalnos is fine. I find the little bit of extra card draw to be good, and spell power + swipe has saved me on several occasions.

1 Zombie Chow?

I've tried with two, but in the end I find one to be sufficient. Having it on turn one is great, but not necessary. It's great in early game and sometimes ok in mid-game when you have 1 mana left-over to spare, but drawing this in the mid-to-late game when you are looking for something of more substance will make you sad. We don't want to heal our opponents too much, we are trying to get them into combo range. Plus there are still a decent amount of control decks + Druid mirrors that you will be facing, and 2 zombie chow is really poor in these situations.

Shredders?

You can use either these or Yetis - I find shredders to be superior just because their deathrattle typically produces a minion that can help finish off one of their minions so you can use your mana more efficiently instead of needing to wrath/swipe/hero power. Of course there will be the occasional bad RNG from it, but 70-80% of the time it produces something of quality. Senjins are an option too, but I find these to be too slow and the 3 attack on them not enough - they are better suited for ramp taunt druids, and you'll have plenty of taunts anyway.