While he obviously has some sort of bias against the ending, there's too much fanboyism in this thread to look at it properly.
He makes a valid point with the relationship between Fakir and Ahiru. I don't know what the people who say that was "developed early" are talking about, because as of the big climactic end of act 1 (ep.13 or thereabouts), she's still hating and/or scared of him until he helps out and not until Mytho starts going all raven-y and they're forced to work together that they get along.
And even then, from a more objective POV, she still goes from pure, fairy-tale, "I give everything for you" love of Mytho and Fakir being no more then an ally to a realistic, "I loved only the ideal of Mytho and realize saving him means saving everyone", I'll sacrifice my happiness for the good of our world thing over the course of one, or maybe two episodes. And it's jarring after 2/3 of a series of "Ah! MYTHO-SAMA! MY LIFE AND EXISTENCE AND PURE LOVE FOR YOU!" It also conflicts with the ideal that only the one who loved him can save Mytho, if she's really about Fakir, all the symbolism aside.
And the series end is definetely not about her accepting "who and what she is", because there's a tangible sense of sorrow surrounding her and the way everything passes her by at series' end. She's content to keep dancing as she is by the side of someone who'll care about her sure, but if she had the choice of staying Human, having everyone remember her, being with Mytho, and getting all the rewards that should have come to her, I think she would have taken it in a heartbeat.