Hearthpwn

"Hate" Druid, because instead of Golakka Crawler OR Hungry Crab, I ran both, because the meta at ranks 5-1 is tons of pirates AND murlocs.

I didn't keep track of my exact w/l, but it took roughly 70 games from rank 5 to legend.

Proof: http://imgur.com/a/pOxH1

A mere 5 upvotes and I'll make a short mulligan guide. Mulligan Guide:

Vs Druid: Usually it's the mirror. Always keep: Innervate (Only 1), Enchanted Raven, Fire Fly. Sometimes keep:  Mark of the Lotus (Only if you can use it on 2+ minions turns 1/2), Mark of Y'Shaarj (Only with a beast), Ravasaur Runt (Only if you can use its adapt turn 2), Vicious Fledgling + Innervate Otherwise, keep at least one 1-drop minion in your hand.

Vs Hunter: Same as Vs Druid, also keep Bloodsail Corsair

Vs Mage: Hard to predict what variant, but always has 9000 Ice Blocks.  Same as Vs Druid.

Vs Paladin: They all play murlocs. Keep at least one 1-drop, or Vicious Fledgling + Innervate. Throw away everything else besides Hungry Crab.

Vs Priest: Same as Vs Hunter, also keep Eggnapper + Innervate and Power of the Wild

Vs Rogue: Same as Vs Hunter, also keep Golakka Crawler.

Vs Shaman: Either Elemental or Nagon Shaman. The latter plays some pirates, so mulligan the same as Vs Hunter, but also keep Golakka Crawler with Coin or a turn 1 play.

Vs Warlock: I saw few warlocks on ladder, so I'd just mulligan same as Vs Druid.

Vs Warrior: Taunt Warrior is the deck's worst matchup, so we only mulligan for Pirate Warrior. Same as Vs Druid, also keep Golakka Crawler and Bloodsail Corsair.

Card replacements:

Patches the Pirate - if you don't have or want to craft Patches, remove him and his Bloodsail Buddies.  Recommended replace with 2x Argent Squire and 1x Dire Wolf Alpha. 

Hungry Crab - No Murlocs at your rank? Replace with Argent Squire. 

Living Mana - Don't. This deck's only real lategame potential and only good lategame topdeck.