For example, it's a tiny bit of a pain to quickly and cleanly access subscribed communities. There's a "subscribed communities" box beneath the right-hand sidebar for the instance you're in, but it seems to me like it should be a stickied item on the left-hand side of the screen, like this:
I'm pretty sure that the devs have asked to not put non-technical discussion on Github, the devs are overloaded enough as it is.
Interesting. My experience is that GitHub issues are very easy to moderate. It's easy to add someone to triage issues if that's an issue, and any load problems usually come from passionate issuers and commentators not following the rules rather than people making well thought out requests.
If there is a real load issue then there needs to be an announcement telling people about it to link to, since what currently exists are guides telling people to use the appropriate places for feature requests and bugs. You also can't tell people to not report bugs for reasons which should be obvious.