Legendary Tiki Young +DEF -ATK

I mean, she has Fierce Breath, 1-2 range, adaptive damage, Bold Fighter, and QR in the seal

I think she's fine even by my refined standards

You might have some issues finding OHKOs against dragons that aren't red, but that was probably the case even without -atk. Look into her matchups with F.Grima and Nowi.

For the rest, I have 50 atk on a partially merged summoner-supported Nowi and I sometimes fail to one-round. That basically means that neutral atk on L.Tiki doesn't always one-round with aether. You're going to have to prepare to fight multiple rounds anyways, so I don't think the atk bane ruins anything. You're tanking better because of the extra def.