I don’t see a major issue here having per-repository issue tracking. On the website we could probably just have separate links for reporting issues for the different projects, and it’s easy to move issues between projects on GitHub in case anyone files an issue against the wrong project. Once the project Readme’s are updated with the link to the individual GH issues page, is there any other place where
bugs.gnustep.org would still be actively referenced? To help with the transition, the domain could just link to that web page with the list of links for reporting issues per project.
I think there’s a significant benefit to having a bug tracking system like GitHub that probably everyone knows from other projects already and that people have accounts for, thereby lowering the entry barrier.