What they're doing with the Raven Queen is giving the DM just the right tools to create a story, while keeping an air of mystery to her.
An enterprising DM who wants to feature the Raven Queen in his campaign and expand on her story may wish to consider making a connection to a deity like Wee Jas to fill in the gaps. While it isn't canon, it can be a lot of fun. I know that my interest in Wee Jas shot up tremendously when I first heard the connection.