Why Diablo 4's loot filter isn't ready yet: 'Every perceivably simple decision has some kind of crazy cause and effect'

Diablo 4 has a big, small problem: inventory space. There's just not enough of it.

Among all the other cool things coming next year in Vessel of Hatred, Diablo 4's first expansion, are a number of fixes designed to help players with the endless bag-space management task that is, perhaps, inevitable in Blizzard's loot-explosion action RPG.

However, it turns out implementing a key player-requested feature—a loot filter—is harder than it might sound. Developers are working on it, Blizzard told us at a BlizzCon interview, but it may not appear soon.

"We don't have a date to announce on the filter, and the reason for that is—let me back up just a little bit here," Diablo 4 game director Joe Shely said. "When you think about the changes we made to experience in Season Two, when we talk about that, we say 40% faster leveling, which is correct. We have data that shows people are leveling faster and so forth. But we didn't just go in and change the number and say, 'Oh times 1.4x.'"

Instead, says Shely, developers made changes to a number of things—the Smoldering Ashes currency that bought Seasonal Blessings in Season One, for example, and making some things multiplicative, like elixirs, instead of additive, when they affected experience points.

"A bunch of things had to come together so that would result in a coherent experience leveling up," Shely said. "The same thing is true for itemization."

In a deep-dive panel at BlizzCon, Shely went over some of the changes the Diablo team plans to make to items: making it easier to compare them, expanding the crafting system and ways to modify your items, and making other tweaks that aim to ensure that item decisions result in meaningful differences in power.

"And so, when we think about a loot filter, we want to get these revisions to the way that our items work in the game [done first], then the loot filter needs to be informed by these changes," he said. "That's why … I can't give you a date."

Associate game director Brent Gibson added that loot filters were one of those things that seemed much simpler than they turned out to be when developers looked into them.

"Every perceivably simple decision has some kind of crazy cause and effect, ripple effect across the whole game," he said. "Sometimes there's low hanging fruit and it goes pretty quickly—and sometimes it's like, wow, that change is actually 120 changes, taking an arbitrary number and pulling it from my back pocket."

Some of the other features under consideration, according to the developers at the Diablo BlizzCon panel, include item loadouts and armories that would allow for swapping out builds. 

Aspects will also be removed from players' inventories and added to the Codex of Power, and Shely said that changes to consumables are being evaluated.

"We have a lot of elixirs, and some of the elixirs … there was an elixir that reduces your evade cool down by 7% and it's like, well, that one might not be the most valuable," he said, chuckling. "I think we have a lot of opportunities in the Consumables tab."