Blizzard made sure they're firing on all cylinders come BlizzCon and fire they did, as the company announced Overwatch 2 and Diablo IV, but they preempted any enquiries for the launch date by saying it will not launch anytime soon.
Diablo IV's game director Luis Barriga said that a game of this scope takes time, and that Blizzard wants to take the time to do it right. He made it unequivocally clear that we're talking about a much later date, because it won't even be "Blizzard soon".
The trailer's description reads, "Hellish new features, brutal challenges, and an indisputable return to darkness lie at the core of our hard work. Take a glimpse into the terror that awaits."
That said, there is a playable demo at BlizzCon, where players can have a taste of what the dev prepared thus far. There are three classes - Sorceress, Barbarian and Druid, with more to be added later, and seasoned Diablo veterans should know them well by now.
Blizzard are promising endless daemons to kill and a deep customisation system through Talents, Skill Points, Runes and Legendary loot.
As for Diablo IV's in-game expanses, Blizzard threw in a few slices of the world of Sanctuary, but it seems to be more like a teaser version of the real thing.
Diablo IV's story is centred around Lilith's return to Sanctuary, which brings with it an age of darkness and misery. Blizzard was probably busy with the demo, so the cinematic isn't as breathtaking as we're used to, but all in good time we guess.