User scores are completely broken, and probably beyond repair.

The low score is not completely unwarranted, though. The game itself is pretty wonderful. But the balancing and QOL decisions made by the developers has been; abysmal, and getting worse with each patch. It sounds like 1.1.1 is going to help a bit, but every the game started with serious issues, and each patch since release has made it worse. Add to the fact that many of the issues have been know since before release, and you get players getting really made about the game.

If you actively make decisions to upset the players, then don't act confused when your player rating tanks.

I don't play Diablo IV (I just don't have the time), so I cannot judge if these scores are warranted. Seeing that it currently sits between Lego Drive 2K and Gollum, I'd go out on a limb here and say that this score seems a tiny bit harsh to me.

Games get review-bombed for the silliest reasons nowadays. Often times, a fundamentalist minority of gamers feels overly protective about "their" franchise, reacting to even the tiniest disturbance with maniacal anger. If a game has a high score from critics and a low score from users, to me that's actually a good sign that the game might even try something interesting (Last of Us II would be an example here). Of course, the critics score for Diablo IV was the post-release score, not including these new patches, so it might very well be that it really is worse now...

Yeah, it turns out no one review bombs unpopular games that they've never heard of.

I'm not a fan of review bombing, and I think it's current player score (2.2 / 1-) is an unfair result of that; the over the top backlash to the changes. That being said, I certainly wouldn't say the 86 / 100 critics view isn't reasonable either. It had issues at release, and it's gotten worse since then. My recommendation would be to give it a few seasons to get into a better shape before picking it up.

It's worth noting that Diablo 3 went through similar pains upon release; though with less "read the room" type issues like they're having now.

That's just cuz a recent patch nerfed some things