I’m not sure I want to remove “all” sorting of the topic list. I too, from a moderation standpoint sort by activity and sometimes post count. I’d likely never sort by the user column though. I don’t see much need for that, as there are other ways of getting that information that are better suited (such as the user’s profile page).
Posts, I would do rarely, as max_posts=1 gets me what I want too. Views, I’d never sort by (or at least, it would be rare – it would be nice to see what topics have the “most” views occasionally though… that’s good knowledge to have when running a community)
And I see no real gain in sorting by Topic. I’ve actually accidentally clicked that and
went “seriously!, why is this sortable”, then I reload the page and move on
Just my thoughts.