As much as I appreciate comments on AO3, it can be pretty disheartening when someone comments for the sole purpose of asking/demanding you add a character they want to see, to write the story a certain way or to update.
I like to call those "jukebox comments" but since we're responsible for our own experience online, it usually helps to block those people, or reply to them with either 'no' or 'not happening' as a way of returning their energy.