Kotaku:

The original plan for BlizzCon 2018, according to two people familiar with Blizzard’s plans, was for Blizzard to announce the mobile game Diablo Immortal and then end on a video in which company co-founder Allen Adham told the audience that a proper Diablo 4 was in development but not ready to show just yet. Instead, at last Friday’s keynote, Blizzard revealed Diablo Immortal to a quiet, uncomfortable crowd and then ended the show. For most of the weekend, Diablo fans raged online as a result, expressing their anger on YouTube and various forums. There were a few reasons for the controversy, but the driving factor was that the company’s sole Diablo announcement was a game that appeared to be made for a very different audience than hardcore Diablo fans.

Huh.

Hindsight being 20/20 and all, bet they wish they did that.