What we have is: https://github.com/CleverRaven/Cataclysm-DDA/issues
This list is surprisingly effective, we have developers submitting fixes to issues there all the time, ranging from simple balance tweaks to major chunks of functionality, but if you’re not a developer this all kind of happens in the background.
As Blaze points out, we have many such lists, of course there are always more tasks than there is time to address them, so it seems like there’s a shortfall, because there is 
I’d be super happy if there was a site that let the users and developers vote github issues up, in fact I’m looking at some solutions for that now, but nothing is looking good at the moment.