Hearthpwn

now that warleader's been nerfed and there's a lot more board clears available this fight is a lot easier. I've put in Blast Wave x2 along with two Volcanic Potions and they work well.

Edit: If you somehow get your hands on a Counterspell, it is a FANTASTIC choice for this fight. The only spells he has are either summon 5 murlocs that died this game or Anyfin Can Happen, which either way just outright 'kills' 5/7 murlocs for 3 mana.

Also, save your Frost Novas for when his board is completely full (and his hand too) if you can. Freezing his board prevents him from playing more murlocs and with drawing 3 cards per turn you can mill a very good amount of murlocs and perhaps even one of the powerhouse spells!

I just restarted everytime I didnt have a good doomsayer and I won after about 5 times, thanks.

Got it first try and didn't even have to use the summoning stones, Thanks abunch! : )

Several tries, and I wasn't having any luck.
Decided to sneak some Old Gods cards in and got it on my first try.
Thanks for the inspiration!
Here are my substitutions:

-2 Ice Lance, -1 Doomsayer, -2 Wild Pyromancer,  -2 Ethereal Conjurer, -1 Summoning Stone

+1 Tentacle of N'Zoth, +1 Explosive Sheep, +2 Twilight Flamecaller, +2 Demented Frostcaller, +2 Cabalist's Tome

Your changes were actually really good. However, instead of running a 2nd Demented Frostcaller & Cabalist's Tome i chose to run a Volcanic Potion (MSoG) & leave a Wild Pyromancer to combo in case Giantfin dropped 1x/2x Coldlight Seer(s) on the same turn. Also, managed to somehow set a 2x Flamewaker turn which helped me seal the game really early with 2x Fireball(s) in hand.

4th try. Swaped 1x Doomsayer with 1x Mirror Image

First try thanks... Doomsayer turn 2 then play it like tempo mage with flamewaker, if you draw summoning stone get it down on 5 in preparation for blizzard or flamestrike bc passed 7 mana he will flood the board every turn. good luck

3rd times a charm!!

This worked for me on my first attempt. Thanks!

This is the ONLY deck I've ever gotten to work. Animated Armor on 4 is 100% win. After that, just keep flamstrike, blizzard, nova, and flamewaker clearing the board. Worst case scenario is eating 7 damage even with a warleader on the board. 

Won on my first try with this deck. Def. needed the Animated Armor on turn 4 tho, the enemy will not attack it for some reason, so this helps mitigate damage.

Wild Pyromancer not working ... wtf Blizz ???? I casted Fireball and no damage from it ... 

Great deck ! Killed on my 3rd try. +1

Thanks man !

Finally. Only took me about 25 tries though, just needed to lucky with my draws and what Giantfin played. In the end, it did work. 

PS- I would HIGHLY suggest removing any two cards and putting in x2 Animated Armor , it really helped me in this fight.

Can someone explain to me how you beat warleader?

One shot him with this one, didnt even have to try out the other decks. The only thing that got out of hand was his freaking Legendary murloc with full board, could' avoid damage from him but still it was dealt easily

First try with this deck I won! Replaced 1 Doomsayer and 1 Wild Pyromancer (because I didn't have them) with 2 Animated Armor which won the game for me!

Works, but I noticed that u have golden fireball but not golden AI, did u just not put it in? Idk y, but it was bugging me XD

Animated Armor is the MVP here.  The AI seemed to prefer going face when I had: Sorcerer's Apprentice, Animated Armor, and Ethereal Conjurer on board.  Giantfin attacked my minions when his board was full and even then, he only attacked one minion per turn, thus leaving Animated Armor alive.  Having said that, you can expect to take at least 7 health per turn so be sure to have a Frost Nova or Blizzard to slow down the damage.

Thanks for the deck!

Did it 1st try. Didnt have Doomsayers, Wild Pyros or Blizzards so I subbed in Explosive Sheep and Unstable Ghoul. Added Counterspell for Anyfin. Summoning Stone gave me Antonidas off of a Flamestrike.

Thanks! Got lucky with card draw and did it on first try with some card changes as suggested by people in the comments:

-1 Doomsayer +1 Explosive Sheep

-2 Sorcerer's Apprentice +2 Murloc Tidecaller

-2 Wild Pyromancer +2 Animated Armor

I left in the Ethereal Conjurers since they synergize well with Summoning Stone. 

Awesome Deck, got it first try with this one!  +1