Hunt for the Truth, the Halo based audio drama was really excellent. I adored every minute of it, and I think the potential for more series to get in on the format is massive.
That is why I'm super excited to see World of Warcraft jump on that train. During a panel at SDCC today, Blizzard announced Tomb of Sargeras, which will be a four episode podcast about how Gul'dan opens a portal letting a a whole lot of demons into Azeroth.
It was also said that if it goes down well, it's likely more will happen.
I certainly hope it goes down well then.