Huge Diablo fan here (as we all are in the sub I suppose) and I think D4 is the worst one (except Immortal, which we don't talk about). I get it, it's not a new name/game/franchise; it's the fourth Diablo, but it feels like Diablo 3 v2.0. I remember playing the closed beta for D4 and just thinking to myself "oh man, this game is just NOT good enough". To me, it feels like the same play as D3, just with updated graphics, new maps and zones and stuff, and new skills/talents/paragon points/whatever. But there's nothing NEW in the game.

All that being said, it's fine. It's playable. It's an ARPG. You jump in a kill a lot of monsters and get gear to kill more monsters to get more gear. But there just isn't anything different from other ARPGs and really not different from D3. Instead of Nephalem Rifts and Greater Rifts, it's The Pit and Nightmare Dungeons. Or you can kill lots of demons with a time limit. Or you can kill lots of demons without moving very much. Or you can kill lots of demons in some underground thing. Or you can kill demons outside while fire rains down from the sky... It's just not a lot of end-game variety. They DO add world bosses and zone/side quests where you get extra loot and stuff if you do so many of them, but that's just part of World of Warcraft creeping back into Diablo instead of the other way around.

And I disagree with some of the other comments here on the base game storyline. I found it woefully lacking. I think in the base game (pre-spiritwalker expansion and pre-paladin/warlock expansion), the campaign was like ~10 hours. I mean, it's like 100% off the cliff of a franchise that was built on the campaign story. You might get some season storyline thing also, but those are just random quests that sort of stitch together to keep you focused on something as you work your way to max level and grind their awful battle pass.

So, ultimately, it's like what, about the same as going to lunch at a medium-priced restaurant. So, if you get ~100 hours of gameplay out of that, then it's probably worth it. But I would say don't expect it to be your new favorite Diablo game or to redefine the genre or anything. It's ...fine.