I assume (based on no real information whatsoever) that either a host of other such legal cases will soon arise over the likes of Wonder Woman, Superman and Batman or are being or have been negotiated behind the scenes. (None of those characters were actually created as Work For Hire -- Siegel and Shuster had created Superman as a newspaper strip before it was published in Action, Bob Kane was under 18 when he sold Batman, William Moulton Marston's deal might have been work for hire, but since it contains a famous reversion clause, I think one can assume it wasn't).