Pronouns are one of the closed classes of words, so attempts to make changes or add words to this category seem impossible and ridiculous. It is almost unfathomable to refer to someone or something as something other than 'he,' 'she,' or 'it.' I agree that language evolves, so I do think change is possible. However, the new pronouns would need to be generally agreed on, and those who want to be referred to using the new pronouns would have to be patient and willing to educate people about their struggles.