In my experience with my other open sourced stuff on Github, others fixing stuff is very rare. Having issues enabled quickly turns into users demanding fixes and no amount of asking for others to chime in aiding with pull requests actually result in pull requests.

IIRC most pull requests come either out of the blue for something new no one has requested before, or they don't come at all until I explicitly say "I'm not going to fix this" and close the issue.