I'm not a moderator, so please correct me if I'm wrong.
I think the best thing we can do to help the moderators do their thing, and thus keep important threads from being closed by trolls, is for everyone to stop feeding the trolls. When a troll shows up and attempts to crap out a thread, don't engage--just report the post, and wait for the moderator to intervene before you respond (if you still feel the need to respond). Trolls depend on this rapid-fire, back-and-forth arguing to generate pages and pages of rhetoric and overwhelm the moderators. They literally hide behind the noise they make.
I think that by not engaging directly with the trolls, we would eliminate the pages and pages of cross-talk that keeps clogging up the discussion, which would give the moderators more elbow room to do their job. And that, in turn, would help keep more of these important threads open for discussion.