I think that the bulk of the complaints is that Unity has become unusable for small developers due to the pricing model changes. It's not unusable in the sense

I think that the bulk of the complaints is that Unity has become unusable for small developers due to the pricing model changes. It's not unusable in the sense of a personal pet peeve, but in the sense of not being commercially viable versus existing options, which include Godot, GameMaker, Love, etc. Maybe Unity no longer cares about small indie developers so they priced them out of the engine, but only time will be able to tell whether they made a major business miscalculation. It's possible that larger developers are the bulk of Unity's income and they will be totally fine with the changes. Still, I don't see a world where what Unity did was a good business move due to the trust issues mentioned by so many other people. I think that a model more similar to Unreal's would have been much better received.