I just unlocked T12 with a bear boulder cataclysm build (P200) and it was a breeze. In T10, my clear speed was pretty much my run speed.
You max boulder and cataclysm as damage sources, then cyclone armor, bulwark and trample (emergency spirit generation). I use Wind Shear as Generator.
Highlights of the build
Extreme mobility and reach: Max movement speed and passive damage in a huge radius that can be cast while running. You pretty much never have to stop.
Semi-perma unstoppable: Malefic Crescent amulet + constant shapeshifting for repeated Blood Howls
Close to 100% crit: Resolve stacking + Boulder mod that gives crit with every resolve (synergizes so well with earth set)
Very tanky: Bear form, resolve stacking + Aspect of Glynn's Anvil, constant Earthen Bulwark through runeword + three defensive skills. I only use one defensive aspect, but I don't have trouble staying alive so far.
Great crowd control: enemies are pretty much perma stunned from earth set bonus
Infinite spirit: permanent cataclysm (earth mod) thanks to Mjolnir ring and cooldown reduction
Fun to play: not having to click on stuff, being able to focus on movement, high damage numbers thanks to earth set bonus, great reach and aoe. You’re basically whirlwinding.
All the buffs & debuffs: Build has constant berserking, resolve, overpower, unstoppable, barrier, fortify, vulnerable, slow, stun, life leech and healing (Blood Howl both)
Notes
Constant shifting: You have to shapeshift about every 4 seconds to keep berserking (from Blood Howl), malefic crescent damage buff, passive werewolf form buffs (shapeshifter aspect), etc. It’s not a big deal though since you have high attack speed and boulders are limited to 5. I simply hold right mouse button for boulder (core skill) while running around and then I weave in left clicks (Werewolf Wind Shear) about every 4 seconds to do this.
Timing buffs: You kinda have to anticipate when Cataclysm will end, because you should prepare and have a full spirit pool when it’s time to recast it (legendary node that gives ultimates +1% damage per spirit)
Flickerstep VS Inner Beast Node: Haven’t found Flickerstep yet so I use Inner beast for cooldown reduction. I constantly shift anyway, but I can’t decide yet which is better.
There is probably still room to improve for this build, but I can create mine in a planner if people are interested.