Blizzard announced a new Diablo yesterday at Blizzcon. Apparently, people didn't get the memo to temper their expectations because they were expecting Diablo 4, but instead boo'd the announcement of Diablo Immortal, a mobile Diablo game.
My thoughts? Cool, a Diablo mobile game. It's like Diablo 3 with new gimmicks on a mobile device.
I'm currently playing Diablo 3 on the Switch which released yesterday (thoughts coming this weekend). Obviously I like Diablo. Always have, always will. There are "multiple Diablo projects" in the works. This was one of them. Personally, I see no reason to riot about its existence. Mobile is a good platform even though it's not my ideal.
What you should be worried about is Netease -- the company Blizzard outsourced. When I saw their logo flash, I cringed. I immediately thought of their game called Crusaders of Light and how Diablo Immortal looks a little bit too similar. With all of their resources, Blizzard couldn't make their own game in-house? I find that disappointing.
Diablo mobile isn't inherently bad, and I'll be willing to give it a shot pending more information on their business model.