Longtime fan of Yar, always thought her leaving was a bad idea. I've wondered if they couldn't have made an effort to bring her back to the main timeline when they were trying to get a new semi-permanent bridge officer in the later seasons and Michelle Forbes wouldn't commit to Ro.
Was always impressed they made sure to get her back for All Good Things...
ETA: If TNG ever gets an Abrams style reboot years down the road, I hope they give the Yar character a much better showing. Though of course she'll probably end up like Gary Mitchell did in the new movie.