Aside from the gender issue, I think a lot of Trek fans are preoccupied with captaincy as if it were the sole and universal career goal of everyone in Starfleet
This is an interesting point. To add to it Sisko wasn't even a captain when DS9 began he was a commander.
I'm happy to read any short story or novel featuring a strong female character, such as a female in command of an away team etc. Many books are going to have some strong female characters and that is one of the things I like about Star Trek, but if anyone wants to recommend novels or short stories where a strong female character is in a center role it doesn't matter if she is captain or not.
I am of course happy to read more books with male captains.