Mulligans
Key differences:
Grumble, Worldshaker – allows you to get value out of the battlecry strong minions you evolve into, as well as healing those minions by playing them again. If you get another one though Earthen Might or Menacing Nimbus, then you can bounce them back and forth and start pulling off broken combos (see replay below).
Al'Akir the Windlord normally good value, but synergizes well with Earthen Might, Flametongue Totem, Bloodlust, and even Grumble, Worldshaker
Check out one of my first games with this version:
https://hsreplay.net/replay/R7fAEwFsc6uzYJhpbtPfgY