Tabletop RPGs have struggled with pronouns more than most places, because they speak through constant examples.

The fighter rolls a '10' on Initiative, and the goblins roll and '8'. He goes first.

A,D&D used the default 'he', throughout all examples, and in the second edition, printed a small box explaining that they chose this pronoun to be unambiguous, but that the reader should understand that 'he' would also include female fighters.

Nobody finds this convincing. When we see 'he', we don't think 'this might mean a man or a woman', we think 'this means a man'.

World of Darkness, more boldly, switched their example pronouns between 'he' and 'she' randomly. The reader might have felt a little confusion, but not too much, and it did the job it needed to do for the reader. The writer might not have felt the same way, however. Tracking pronoun usage, and marking up uses of 'he' vs 'she' with tally marks does not make for a good workflow.

Next up, we have the classic, 'they'.

The fighter rolls a '10' on Initiative, and the goblins roll and '8'. They go first.

You can spot the problem easily because you're looking for it, but once it's part of a larger chapter on combat, spotting it becomes much harder. The simple advice of 'try to write unambiguously', has to push against every standard instinct, because in any other circumstance, we write unambiguously with exactly this pattern of pronoun. Singular vs plural has always been clear; suddenly it traps you, but only when writing about generic fighters and goblins.

Finally, we come to the neo pronouns. They solve all the problems.

The fighter rolls a '10' on Initiative, and the goblins roll and '8'. Sie goes first.

Looks a little weird, but crystal, fucking, clear. This also allows the writer (me) to write without constantly checking for unexpected ambiguities, so I grabbed them for my tabletop RPG book.

Out of all the options for neo-pronouns, I went with 'sie', and 'hir', because they look friendly. If a different neo-pronoun emerged later, I'd simply adopt that instead.

Why I Didn't Adopt Them

A few people, mostly in my university, read the RPG book. They picked up the pronouns easily. The US audience, however, had more problems. Perhaps they had general literacy problems, but more likely they just couldn't stop thinking in terms of teenagers on Tumblr adopting strange pronouns for the sake of fashion. However clearly the book's little box (a reference to that same box in the A,D&D book) said that the neo-pronouns served clarity and nothing more, anyone over the pond seemed fixated on Tumblr teens.

That much I could handle, but after some years of neo-pronouns, no consensus had formed. If these words could have survived, only one set could emerge victorious. A language of constantly shifting pronouns for each person will never exist.

This weak-sauce failure to unify ended the experiment.