Allow me a quick introduction. My name is David, screen-name ZealousPawn, and you may or may not know who I am. I'm the founder of Team Chess, what I believe to be the strongest collection of non-pro players in Hearthstone. I've finished the last two seasons in the top 100 of ranked play in NA, and last season (June), I did so with this deck. Let me say that I do not believe this to be a fluke or a gimmick. This is a legit deck, and I think you will see it enter the meta at the top levels. I am not a well-known tournament player or streamer, but I take pride in being a strong deck builder and believe that I am ahead of the meta again--as I was when I created a strong Hybrid Hunter in March--long before Hybrid was considered viable. I created that deck to see if I could get King Krush to legend, but it is still a strong decklist today if you switch out King Krush with Leeroy Jenkins and add in Quick Shot (a card that wasn't released yet). Back then, nearly everyone was playing exclusively mid-range or face.
About the deck:
I finished top 100 legend with a 65% win rate (53 wins, 29 losses) with this iteration of the deck. This is not an inflated number as ALL of those games were played in ranked play after having already achieved legend. Proof of top 100 legend finish here.
This is a minion-heavy Oil Rogue deck. The pirates just happen to have great synergy. Unlike other Pirate Rogue decks before, this is not some gimmicky deck that just goes face and runs Cold Blood. This plays much more like a traditional Oil Rogue--and as such, it is not an easy deck to play. But it's a ton of fun!
Good Match-ups: Druid is helpless against this deck. Patron Warrior is a strong MU, which makes it very good right now. There is no healing, but this deck actually does very well against most aggro decks, including Hunter and Aggro Pally. Ship's Cannon does work.
Bad Match-ups: Ironically, Oil Rogue is a bad MU. I believe my list is an improvement on Oil Rogue in most MUs, but the extra minions and fewer spells make it vulnerable in the mirror.
Mulligan Advice and Tips:
Every match-up is different, but to generalize--you want to get a fast start against aggro, and you want to take it slow and choose your spots against control. Harrison Jones is in most control decks these days but fear not! They won't always draw it, and even when they do, it is usually not game-breaking. Don't be afraid to dangle a 1/2 or 3/1 weapon as bait for him. During mulligan, keep Preparation+Sprint in opening hand if you have both in every MU except Hunter. Each MU has what I consider a "pressure point"--this deck has insane tempo, but you have to choose the correct moment to seize control. Against aggro, that is usually as soon as possible; against control, it is usually around turn 3-6. Let's look at the Mus individually:
You don't have any heal--but don't worry, you have tools to deal with Hunter. This is a MU that favors you, as you can usually outrace. If possible, get off to a fast start. Mully for: Backstab,Deadly Poison,Bloodsail Raider, Ship's Cannon, SI:7 Agent,Dread Corsair. You can even keep Tinker's Sharpsword Oil if you already have a Dread Corsair and don't have Deadly Poison.
Keep an eye on his mulligan and try to guess if he is Zoo or not. The more cards he keeps, the more likely he is Zoo instead of Handlock or Malygos. You will mully differently based on what you suspect he is.
Against Zoo: You have a good MU. Look to be the aggressor if you can. If you can't, then sit back and wait for a good tempo swing with Ship's Cannon/Corsair combos or a Blade Flurry to get in control of the board again. Mully for: Backstab,Deadly Poison,Bloodsail Raider, Ship's Cannon, SI:7 Agent,Dread Corsair. If you are not sure he is Zoo, it's also OK to keep Sap.
Against Handlock or Malylock: you have to be careful not to overextend. If you play a bunch of 3 health pirates and they all die to Hellfire or Shadowflame, you will be sad. Try to only have 2 or 3 minions in play at a time unless you have to all in. Try to bait out hellfire before building a big board. Against Handlock, you can play much like a Combo Druid does--if you can maintain a decent board state, you should be able to burst him down with an oil combo from about 15 health. Against Malylock, just try to apply consistent pressure until you win. Sometimes you will burst them down; other times they will not be able to tap much and will be forced to use removal on your minions, and you will just win because they run out of options. Mully for: Sap, Azure Drake, Sprint.
You have to assume that it is Tempo Mage or Mech Mage, and just adjust on the fly if it is Freeze/Giants Mage. You mulligan to play against aggro, but unlike the Hunter and Zoo match-ups your early minions can be easily removed by spells (like Frostbolt and Flamecannon. They are also susceptible to die easily to Flamewaker paired with cheap spells like Arcane Missiles). Therefore in your mully you're looking for removal: Backstab, Deadly Poison, Blade Flurry, SI:7 Agent are your priorities.
Against Freeze Mage: you might not know you're playing against it until turn 3 or 4. That's fine... the name of the game is pressure. Don't flood the board with minions, that's the wrong way to pressure with this deck. Your minions are cheap and can all die to one Flamestrike. Rather, try to have 2 or 3 strong minions out (like an oil-buffed minion and a Drake, or oil-buffed minion and a Bloodsail Raider that got buffed from her battlecry. Don't waste Bloodsail Raider in this MU. The idea is you get Freeze Mage to have to waste her Frostbolt and Fireball cards as removal since you hit before Blizzard/Flamestrike comes out. And even once you get to turn 6 and turn 7 there are few minions on board anyway.