update: Blizzard issued a statement to Kotaku denying that he intended to announce Diablo 4 at BlizzCon. "Generally, we do not comment on rumors or speculation, but we can say that we have not drawn any announcements from BlizzCon this year or we do not plan other announcements," said the representative. "We still have various teams working on many unannounced Diablo projects and we are waiting for the announcement when the right time will come."
Kotaku said that the video in which Allen Adham discusses the new full-blown Diablo project has been made; what has not been confirmed here is whether it was actually intended for BlizzCon, or if it was simply an idea that was thrown out and then rejected. Regardless, the site claims that Diablo 4 is in development, but it looks like it has not gone smoothly yet: "heard" that the new Diablo has gone through two iterations under different directors in the last four years and can change With the development of.
The Diablo Immortal announcement in BlizzCon went as bad as it could have been. Revealing the game on mobile devices instead of the full Diablo 4 has led to "enormous opposition" to what traditionally is a two-day celebration of all Blizzard's stuff. According to Kotak's report, the reaction to the Diablo Immortal advertisement could have been very different, because the party claims that Blizzard planned to confirm that Diablo 4 is in development, but it saved it by the end of Friday.
Two sources familiar with the situation told the site that the original plan was the announcement of Diablo Immortal, and then a video in which co-founder Allen Adham confirmed that Diablo 4 is in the works, but is not ready to be shown yet. The move sounds like it is very similar to Bethesda's announcement of Elder Scrolls 6 on E3, a completely irrelevant statement of the obvious, but he still had fans in a much happier scar.
But for unknown reasons, the plan changed a few weeks before BlizzCon, and Diablo 4 was scrapped. One of Kotaku's sources said that Blizzard decided he was not ready to engage in the announcement because development is constantly changing and the game can continue to change as it grows.
This in itself does not explain why Blizzard would decide to pull the plug. It's not like Diablo has to be explained right now – as in The Elder Scrolls games, each new iteration changes, but the basic experience remains basically the same. In this way, Bethesda was able to get a roaring applause, just splattering the four words on the big screen on E3, and Blizzard could easily do the same: Tell the audience: "One more", smash the Diablo 4 logo on the screen, "Thank you goodnight!"
I found out that Blizzard has more information and will update if I get a response.