Well, our characters already were exposed to such aether before: in DRG story when WoL became second Azure Dragoon. So First Brood aether is not something new and entirely alien to WoL - we blasted Ascian while channeling it, too.
And Hresvelgr willingly gifted WoL with the power of his Eye, while channeling Nidhogg's aether required strong will to defend against madness and rage of it's real owner - we already freed Estinien from NIdhogg's control in lvl50 DRG quest through Echo-sort-of-thing, summoning spirit of first Azure Dragoon to guide our legs in Ultra Dragonfire Jump
And that brings another question: we tossed Niddy's Eyes into abyss (now it will stare at us for all eternity) and returned Eye to Hresvelgr. Is WoL STILL the Azure Dragoon? Or did he lost the ability to power up goony-things?
Also, in the post-MSQ quests, Middy talks to Tiamat and says about his hope that alliance between man and dragon will be the foundation of force against the coming darkness.