I really dislike Raekor + IK charge, but for sure it has very impressive damage in large AOE packs and Earth (Boulder Toss or Seismic) cannot compete with that, on boss damage though Raekor isn't that impressive since Vile Ward is no longer in effect, nor do the Ancient Parthan Defenders have the same effect.
I'm doing a lot of rifts at the moment in a 3man group with an Impale Demon Hunter and Raekors Barb (I'm playing SS) and we're farming 75s pretty quickly, I'm at a situation where I can just stand on the spot and heal through almost everything, with only physical damage being scary (since esoteric does nothing), where as the Raekor Barb during the whole rift will only fight mobs until they are stun immune and then he will leave and find new stuff and leave me + DH to deal with it.
In solo the Raekors is still clearly the best spec because the damage on large packs is so much stronger than other builds, but the spec is still quite prone to death and it's such a clunky and situational spec to play, I just can't stand it. My Seismic Slam build will take me far enough, it will run out of steam in the early 80s though from lack of damage scaling, where Raekor will keep pushing on.
I've not played Boulder Toss (with Tribes Blade) enough to really compare, but SS seems in a similar place but while being far more about the spender than the generator, with SS the Earthquake/Avalance is more like a filler damage to activate Earthen Might so that you're at high Fury and full toughness (from Iron Impact + Band of Might) just before the fire element on COE comes up. My latest crit records are over 200bil on RG.