[Egil]

Mayelia doesn't even heal from all stuns (Chaos and Kunai can confirm this), so it is situational and not overbearing if you can outdamage a Dullahan- which is not an immense feat at all. And regardless, a Dull spamming high FP moves in an attempt to constantly stun themselves is better off building FAI and just going Priest in order to heal themselves for 25%+ max HP for 7 momentum over the course of two turns, whereas stunning yourself with Mayelia only gives 15% for that entire 7 momentum.

And, funnily enough, you can heal yourself frequently as a Dull with Priest/Curate because you never run out of FP.

If you're that worried about Dullahan Sustain builds, then make a case for nerfing Dullahans (which I don't see a reason for, either) and not a sub-par armor.