I think another good idea for Wordtube would be to "make a bridge" with the Genki Youtube Comments (http://ericulous.com/2007/05/16/wp-plugin-genki-youtube-comments/) : this plugin is really great. It allows to retrieve the comments of a youtube video (adding the video ID as custom field) in a post.
Actually I'm using the two plugins and it's working nice. But I have to add each Youtube ID manually for each post.
It would be great that you add an option to detect this automatically if Genki is installed or something like this !