From: http://closing.vox.com/

"To help you make the transition off of Vox, we’ve added new export features that make it easy to move your blog to a free TypePad account, and your photos & videos to Flickr."

So there are already ways for ex-Voxers to make sure their content doesn't vanish. Importing here would be nice if people specifically want to get started with Dreamwidth, but a backup service isn't urgently needed, as far as I can see.