I think the current castings are great as they are. My problem is that it is very hard to know when they are even doing this.
Voobly don't have a presence on facebook, twitter, reddit, even youtube, where they can announce upcoming streams. Even the events calendar here is usually only updated a few hours before a game goes live. Voobly cast expert games with entertaining commentary but nobody knows that it is happening.
They have all of those. I don't know how much they use them though