I don't think there is a single WoW or Warcraft III fan that would not watch this series. Arthas is one of the best characters in WoW history. Furthermore, the hype for World of Warcraft Classic is huge, and the best time to announce such a series is now. Combines with the Blizzard animation team, they literally can not mess it up. It would make all the fans overjoyed, while also making a gigantic pile of money.
Blizzard should create a animated miniseries primarily focusing on Arthas, on his journey that would ultimately result in Arthas becoming the Lich King.
The Blizzard should make a Arthas/Lich King miniseries petition to Blizzard was written by Mihovil Biloglav and is in the category Films & Movies at GoPetition.