I recommend the 1989 annotated version of Ursula LeGuin’s essay “Does Gender Matter?” about the question of pronoun usage and its social implications. It’s anthologized in her splendid essay collection ‘The Language of the Night.’ She was writing it in the '70s regarding her use of ‘he’ as the generic third-person pronoun for the double-sexed characters in ‘The Left Hand of Darkness,’ but some of the same issues come up in the contest of modern trans identity.
You may or may not agree with her conclusions but it’s an interesting read. She herself originally felt that “‘he’ is the generic third-person pronoun in English, dammit” but later completely reversed her decision to say that “they” should be used, and “let the pedants and pundits squeak and gibber in the streets.”
Now, ‘xir’? I, um, yeah. Dunno about ‘xir.’ But languages have been evolving since time immemorial.