Safe to say that many weren’t thrilled by this, with some saying that this would not have been as bad had Blizzard at the very least announced Diablo 4. Some also likened it to Bethesda’s announcement of Fallout 4 which was preceded by the announcement of Fallout Shelter. However as it turns out, Blizzard almost announced Diablo 4 at BlizzCon, according to sources of Kotaku.
According to the report, the initial plan was that Blizzard would announce Diablo Immortal and then towards the end, they would confirm that Diablo 4 is in the works but also that they weren’t ready to show them anything yet. However in the weeks leading up to the event, Blizzard cancelled those plans as the team did not feel like they were ready to commit to an announcement due to the fact that Diablo 4 has changed drastically in the past four years and is still doing so.
Basically it sounds like Blizzard wasn’t ready to announce Diablo 4 as they felt that it was still not quite far along in its development to share concrete plans. However many fans feel that at the very least, an official confirmation would have been nice, although Blizzard has since reiterated that they still have multiple Diablo projects in the works, with Diablo 4 presumably being one of them.