* Separate "Issues" and "Requests", give each their own tab in the top-level UI. This creates a relatively clean separation between what requires attention because something is broken and what can be ignored until you want ideas for what features can be added or otherwise improved. Maybe GitHub doesn't need anything more generic than this.
* Have a category system, where the maintainer can create their own issue categories. Put these categories, with the number of entries in each category, in the sidebar, so that that's what people see rather than the one "Issues" number.
Maybe both of those solutions are bad and a good UX designer (not a random commenter on HN who has thought about this for 2 minutes) can think of something better. Maybe both of those solutions are bad and there is no good solution and the current approach is the best possible. I don't know. Notably though, "there is no solution to the problem that's not worse than the problem itself" does not mean the same as "there is no problem".