Suggestion: Make the ancient crystals' benefits (chance to land The Primal Rage or Fangs of Fury) as passive abilities, and remove the crystals. And grant both sets of benefits to all ancients. It will help remove the faction from the combat style equation (which I have made detailed points about in other threads).
If they will do this, you will still get your benefit of the ancient combat crystal as well as use one of the epic claws. I'm hoping this idea is considered. Allowing both sides the use of either elemental breath attack was the first half of untying combat from the (political) factions. This idea is the logical second half.
If they choose to make it a crystal no matter what, so that the player is forced to decide whether to use the crystal or an epic claw (bad idea since being ancient should have inherent benefits, not ones I have to give up something else for), then another solution would be to add both sets of benefits to both crystals, and then changing it into a jewelry crystal for use in a headscale, so that the Epic claws can be used. The other option would be to add a weapon socket or 2 to the Epic claws.
But the better solution is make them passive abilities, AFTER they finally get the delay modifiers fixed again on The Fangs of Fury. (Broken since 2010 or longer).
If the ancient effects were made passive, those claws (blood and demon) would be in higher demand. As it is they have to compete against Claw techs + fangs of fury or the primal rage which is almost always no contest, even after the recent improvements made to the Epics. Choices are all well and good. But an AROP benefit really shouldn't be something you give up to use a Demon claw.
I'm not a fan of eliminating the differences between helian/lunus dragons. I like the deliberation of choosing one faction or the other and part of that is the abilities each gains with the arop.
As far as helian and lunus combat differences above, remember this: Some of us chose a side before any of this was known/in game. I know I did. The only differences back then was the 20 t&c vs 20 primal and the ice/spirit vs flame resists. In my opinion those rop differences themselves are enough of a difference between factions, that's decided then (when character is still relatively young), and is adequate to satisfy the lore differences talked about during rop. Further differentiation can be one or the other questlines, ancient schools, etc. Faction is a political alignment, nothing more.
Perhaps let me make a different suggestion (the heart of which was originally proposed to be a part of AROP): After completing AROP, the Ancient Dragon may visit the council of Elders and change factions if desired, swapping the weapon crystal for the other sides' at the same time. This change can be made back and forth with no limit. In this way, a Dragon can "multiclass" his combat style as desired. But really, swapping factions should be a do-able thing, just for lore and role playing purposes. Combat (the AROP crystal) really shouldn't be tied to that. Perhaps just give V'Tierru the capability to trade the AROP crystals back and forth, while leaving faction alone? Ugh, but this is so messy.. just please make the effects passive.