I think there's a third big thing: really good UX. I don't have an Android phone, so I don't know about Jerboa, but the web interface ... could use some work. I know the bug with new posts pushing the feed down is on track to be fixed soon, but wow, it can be really quite bad. iOS apps are getting way better quickly, too, but overall they're nascent.
I can't quite put my finger on it, but additionally, I think the ranking algorithm(s) could use some work. I can see there's tons of content, if I sort by new, but sorting by active results in stale posts, and sorting by hot doesn't seem to quite hit the sweet spot on tenured/good quality content vs. newness. The recent ranking bug(s) haven't helped matters there either.
I remember reading a detailed post with a list of concrete mod tool improvement asks - things like the ability to filter the modlog to local only, or auto-report posts or comments containing certain keywords. Can anyone else find that? My searching is coming up empty. Maybe I dreamed it.