Diablo 4 lead class designer Adam Jackson says some features that were widely maligned simply didn't go through enough testing for Blizzard to realize they were tedious in design.
Talking to streamer Raxxanterax (timestamped here), Jackson explained that the Diablo 4 team's process of internal feature testing today is a little more robust than it used to be.
Although it's not clear exactly what's changed, it sounds like the developers simply put more time into making sure new features will be positively received. "This is where you get things that seem obvious to players that were bad ideas but sounded like good ideas when we're sitting in the room talking about it," Jackson said, pointing to an example from Season 4's new tempering system in which an unskippable animation is played when tempering items. "Sometimes things fall through the cracks of, 'hey, doing this 2000 times is actually terrible because you have to wait forever' versus 'well, we want a moment of celebration and for the cool thing to be cool'.
Balancing these things is what can be harder to do internally. We've made that mistake enough times that now we're very cognizant of it.
We make a new feature or new activity and we're like, 'hey, how does this feel doing this for 200 hours?'" Of course, it also helps that Diablo 4 Season 4 is the first season to be put through a public test realm before making the jump to full release, giving testers plenty of time to identify pain points and communicate them with the developers.