Diablo III is arguably the weakest link in Blizzard's current portfolio, and, although the company is not really pressured by upcoming Korean MMOARPGs, it at least owes it to the fans to hype things up for the Diablo franchise once again. Blizzard acknowledged the existence of multiple Diablo-inspired projects already in development, some of these being scheduled for a reveal at Blizz Con this year.
https://www.notebookcheck.net/Blizzard-has-multiple-Diablo-projects-in-the-pipeline.321278.0.html
The video is thin on specific details, but a huge hype infusion for Diablo fans. That all we needed for now, to know that the franchise is alive and with a future.
There's a lot of speculation about what those "multiple projects" would be, and this is nice to have. Brandy doesn't say Blizzcon for some of the reveals, but it's almost assured to be the case.
Big projects may include D4 or some sort of "Prequel". For smaller projects, we may have new character packs for D3 (Druid?) of even another expansion, D1 and/or D2 remasters, Nintendo Switch port, comic books, a trading card game, a mobile game and more.
Anyone interested on some fun speculation should check YouTube videos from the well known D3 streamers, like Rhykker, Bluddshed, BigDaddyDen76 (aka Anthony Evans), LeviathanD3, Wolfcryer, PChild or Dropaduski.
You can be srs and expect smth good from EA Blizzard. It will be generic low quality story generic mechanic game in Diablo setting.