In addition to replacing UserVoice, would it also be a good idea to replace the blog itself with Meta? Given WordPress' recent flakiness, I think that a more stable replacement is in order. The idea isn't as crazy as it sounds - a blog moderator tag could prevent people from posting their own stuff in the blog, and locking the post would prevent people from being able to edit it. All that's needed is a few custom pages styled similar to the existing blog but generated from the content on Meta instead of the WordPress database.
Granted, there are downsides - this could put some additional load on the database, and another mechanism would be needed to report outages (I recommend Twitter), but on the whole I think that the discussion capabilities of Meta completely outclass what WordPress offers now, not to mention the fact that the discussion can happen in a single place, as opposed to fragmented across the two sites.