Pyroak is definitely tearing shit up. Grass/Fire STAB means it hits water, steel, ground, and grass for super effective damage, including virtually every physical wall in the metagame.
the common set is:
~Earthquake/Dragon Claw/Stone Edge
Fire/grass isn't amazing type coverage, but it's perfectly acceptable given that it hits almost every physically bulky pokemon for super effective damage, including hippowdon, skarmory, forretress, metagross, celebi, vaporeon, suicune, swampert, arghonaut, and shaymin.
Earthquake covers heatran, one of the few pokemon that can stop this rampage, leaves it vulnerable to salamence (though salamence takes takes around 41 % from an unboosted flare blitz anyway). Dragon Claw OHKOes salamence at the expense of losing to Heatran. Stone edge is the compromise, hitting heatran neutral and OHKOing salamence, but then cyclohm becomes an issue. Stone edge does nail other Pyroak though (Pyroak with Flash Fire is one of DDOak's best counters). cresselia is the only wall that i can think of that pyroak can't hit super effectively.
In all the excitement about Pyroak, Revenankh's new possibilities haven't really been explored, but revenankh is unbelievably bulky now. The spread using 216 sdef EVs before is equivalent to only 56 EVs now, leaving 160 available for defense, attack, or more even sdef.
compared to some other walls:
252 Naive Life Orb Infernape Fire Blast
vs. 252/252 Careful Revenankh : 35.5% - 42.1%
vs. 252/4 Impish Hippowdon : 67.4% - 79.5%
vs. 252/252 Impish Occa Berry Skarmory : 64.7% - 76.3%
vs. 252/0 Bold Suicune : 24% - 28.2%
vs. 252/4 Impish Arghonaut : 26.1% - 30.9%
252 Naive Life Orb Infernape Flare Blitz
vs. 252/4 Careful Revenankh : 60.5% - 71.4%
vs. 252/252 Impish Hippowdon : 33.6% - 39.5%
vs. 252/4 Impish Occa Berry Skarmory : 44.3% - 52.4%
vs. 252/252 Bold Suicune : 17.8% - 20.8%
vs. 252/252 Impish Arghonaut : 19.6% - 23.2%
252/4/252 Careful Revenankh : 96% - 113.5%
252/252/4 Impish Hippowdon : 101% - 119%
252/4/252 Impish Occa Skarmory : 109% - 128.7%
252/252/4 Bold Suicune : 83.6% - 98%
252/252/4 Impish Arghonaut : 91.4% - 108.2%
suicune and arghonaut numbers doubled for comparison
Revenankh ranks among the best mixed walls in the metagame...