Off Hand Only Why?

[Rearden]

Proc both fist gogo.

[Taint2]

It's not just Empyrian and Mythic H2H weapons, Spharai is the same way, OTD is only for Main Hand. They changed ToM OAT H2H probably because you can dual wield OAT Magian weapons along with a kc, ridill, or other Occaionaly Attacks multiple times weapon. Now since H2H has always had a pseudo-dualwield effect but no OAT knuckles prior to this(we'll get to mythic in a second), they never worried about it. Every dual wielder can have weapon A with OAT and weapon B with OAT, so you have to allow both fist A and Fist B to have the OAT to make it fair.

Now why Mythic/Empyrian/Relic only proc on one hand you only have to look at balancing towards dual wield just like they did with ToM. In all cases of any of the 3 "Ultimate" Weapons when in the sub slot, or weapon B as we'll call it, none of these bonuses apply. You don't get 2x, or 3x Relic procs while off handing, you don't get Aftermath on offhand Empyrian or Mythics. H2H Ultimates only allow 1 hand to proc bonuses whether it be Main hand with Relic, or the Sub hand with Empyrians. This is not broken at all, and although I'd love my Spharai to 3x on both fists, and Vereth to ODD on both, it never will. This is intentionally coded in to balance it out with not allowing bonuses on offhand Ultimates.

Everything you said is correct but its still a huge disadvantage for H2H and dual wield weapons when compared to the 2handers.