I thought Greg Egan used "ve", "ver" and "vis" as the subject, object and possessive pronoun respectively. I think I read it in in Distress, back in the late 1990s and it was a new idea for me at the time. Has he changed his suggestions since then?
I think you're right, actually. It's been a while.
The point is that when you read them in context it takes zero mental energy to just accept them. And, when you're talking about post-humanism, it even side-steps all real-world considerations of non-binary or trans issues.
For example, the first chapter of the novel
Diaspora describes the birth of a virtual entity, from the initial formation of virtual neurons, through its process of actualisation through social interaction, up to the moment of self-awareness (first use of the term "I"). It's a living, conscious entity, but it hasn't yet got a full-formed brain or personality, or a (virtual) "physical" form. The former means that "it" isn't really appropriate,* and the latter means assigning a gender isn't appropriate, either. There's not even any guarantee that it
will settle on a gender.
And, as I said above, I think that words like "vir" work better
in principle than "they", simply because "they" can be awkward and is more open to ambiguity.
For example, consider the following sentence pairs:
"They approach the group. They introduce themselves."
"Ve approaches the group. They introduce themselves."
"Ve approaches the group. Ve introduces vimself."
The first could mean the same as either the second or the third. Sure, you could write around it ("they introduce themselves to the group"/"they introduce themselves to each other"), but the very fact that you have to to avoid ambiguity demonstrates that it's a sub-optimal form of communication.
And, come to think of it, I'm not sure that you can keep basically the same structure and clearly communicate that the group introduces itself to the individual, while the individual doesn't introduce themselves to the group. With "ve" it's trivial:
"Ve approaches the group. They introduce themselves to vim/vir." That works.
"They approach the group. They introduce themselves to them." That doesn't.
Even substituting "the group" at the start of the second sentence creates problems, because then you have to start treating it as a singular you get: "They approach the group. The group introduces itself to them.", which is even more awkward. You basically have to write the whole thing differently. You may end up with better-written sentences, but the point I'm making isn't about the aesthetics of the prose, but the utility of the words.
I don't think there's an easy solution in English, really. As I say, I think that "they" will likely take hold eventually, because that's the way it's going and young people will grow up being used to using it, but I don't think it's ideal. I think that "ve"/"xe"/"e", etc. are better but, absent a huge campaign which also gets mainstream publications (newspapers, etc.) on board, I don't think it's going to happen. And I don't think it'll ever be as easy as Sweden has apparently found it, if for no other reason than because it's not the same linguistically.
*Although it's possibly worth saying that I'm re-reading some E. Nesbit children's books ATM, and she does constantly refer to the children as "it". Sentences like "each child put its hands in its pockets". I'm not suggesting this would or should ever come back, but it is interesting to read "it" being used as a gender-neutral term to describe human beings, in a mainstream childrens' book, albeit one from a long time ago.