Yeah, this sounds like a pretty good idea. I don't have any idle hubs, so I don't have any first hand experience with what to do to get it out of idle status, but moving it to another website seems like an option.
As you mentioned, however, the hubs are idle because they don't get much traffic, which is probably because it is not a popular topic, or some other issues. So just moving the articles to another site may or may not affect how much traffic you get.
Perhaps even starting a blog and adding idle content to that would be more beneficial, especially if the content is all on the same topic.