It looks as though Blizzard had originally planned to tease Diablo 4 during Blizzcon 2018. Instead only the new mobile title Diablo: Immortal was announced at the conference which has not been received favorably by many fans.
Kotaku reports that two sources with knowledge of Blizzard’s show plans confirm that the company was planning to show some content relating to a core Diablo title. Apparently after Diablo: Immortal was unveiled, another announcement video was planned to air. It would feature co-founder Allen Adham who would tease Diablo 4 but also explain that it was not ready to show to fans.
Apparently, the plans to show this video were changed in the weeks leading up to the conference. This lines up with the blog post that Blizzard released two weeks before the show, which attempted to inform fans that Diablo 4 was being made but would not be present.
It’s fairly common for Blizzard to not announce games until it is ready and it seems that’s what happened here. Sources are also saying the company wasn’t ready to commit to a Diablo 4 announcement.
The reason for this is likely not wanting to show fans anything that is still likely to change. Diablo 4 has reportedly gone through two iterations with different directors and has evolved massively during its four years in development. Concern over upsetting more fans indicates that there may still be major changes to come before we will hear anything solid about this next Diablo title. While a natural part of game development, changing games before release has gotten other companies in hot water like CD Projekt Red and Insomniac Games.
It’s worth noting that Kotaku news editor Jason Schreier also posted to his Twitter account saying that “you’ll have to trust me and my track record when I tell you that Blizzard didn’t want me running this story” when fans questioned whether or not this was just damage control from Blizzard.