Mulligans
Aggro Mulligans
Hunter and Paladin being the most popular aggro decks these days, these are the cards you absolutely need against an aggro deck, two of your early minions to take trades and gain some armor while trying not to lose board and also because the Whirlwind effect takes down easily all the cheap minions (especially Silver Hand recruits).
Control Mulligans
Against Cubelock or Warlock in general you should always keep a Spellbreaker because of minions like Rin, Voidlord, etc. And also, keep the Ooze because Skull of Man'Ari is played in a lot of versions and it's way too strong for you to let it several turns.
This is a deck I’m currently trying to build and reinforce because I think it has a lot of potential. The basis of the deck is to play Genn Greymane which will allow you to armor up a lot, combined with what I would call “Armor synergies” of the warrior : Geosculptor Yip of course but also Gemstudded Golem which is very nice against aggro and finally Bladed Gauntlet. I found this weapon absolutely excellent against Cubelock because you can take down big threats easily as you could do with Gorehowl, I’m still wondering if a second copy could be included.
Other cards help you gaining as much armor as possible : Drywhisker Armorer, Armorsmith, Plated Beetle and Unidentified Shield.
Apart from the armor mechanics, the other win conditions are The Lich King and Rotface combined with Warpath or the hero power of Scourgelord Garrosh (don’t play the DK too early in order to maximize the value from the basic hero power, armor is the essential aspect of the deck).
Obviously the classic turn 4 which is a must-have because of cubelock / Warlock in general : Spellbreaker. One more thing, Rotface can be replaced by Grommash Hellscream, this legendary is funnier than competitive but it fits pretty well and gives some value to Warpath in slow match-ups. You can add Inner Rage if you do this replacement because 0 mana cards are considered as Even-cost cards.
Update : Bloodmage Thalnos was added in order to have a little more card draw and it’s always nice to have a 2 damage Warpath on turn 4 against any kind of aggro deck.
This may not be a top tier deck but I’m pretty sure some Legend Warrior players will try such archetype, from my experience I can say it’s a good counter for Cubelock and if you get Blood Razor and Warpath in the right timing you can also take down Dude Paladin (the Even version is way easier to beat compared to the Odd one). I also had a lot of fun playing it so it’s worth the try ð
If you can squeeze in a Warpath or two you should improve your odds vs Paladins a bit – timing it right is the trick though.