Diablo 4 doesn’t have a fundamental design issue, but it’s acting like it does. Let me explain myself. Not so long ago, Blizzard responded to a criticism regarding the lack of interest in treasure goblins by… increasing their Legendary drop rate to a 100%. They also justified increasing the difficulty of bosses by guaranteeing a legendary item drop. So it would seem like Blizzard believes legendary items are the end-all be-all of the game. The thing is, if this was true, it would indicate a fundamental design issue. To understand this, we need to first analyze what legendary items are and what their design purpose is.

Legendary Items are just legendary aspects

Legendary items are rare items with the addition of a legendary aspect, affecting, transforming or improving some of your skills. They are, using Blizzard’s words, “build defining”. We also have the ability to extract and move these legendary aspects. Following this logic, farming legendary means farming legendary aspects, which by extension means farming "build defining" or more commonly, "build enabling" abilities. 

The "enjoy your character later" issue

Now if we accept the apparent Blizzard's premise, that legendary drops are the ultimate reward, we get a design issue we commonly find in TTRPGs, that I like to call "enjoy your character later" (shoutout to my Pathfinder 1e Dimensional Assault friends). RPGs, wether Action of TableTop, are often all about enabling fantasies, something like a thunderlord werewolf (just a random example that has nothing to do with my current Druid build, I swear). Unfortunately sometimes, often in the name of power balance, the very core of the build you would like to play can only be unlocked at a later level, or through an end game item. This is, quite simply, bad design. Selling the promise of fantasy fulfilling builds to a player, to then make them go through half the experience with a unsatisfying, or worse unusuable build, is creating expectations to disapoint. 

So are the designers at Blizzard just bad?

Well ... no. No one is perfect, and a lot of people are bad at their job. But you likely do not end up in a high-level decision making position working on a legacy franchise like Diablo without understanding a fundamental design principle like this one (hell if I can think of it, I am certain they did, and way before I had the time to type it). So the idea that an entire team could have missed something this big is very unlikely. And we have evidence of this. The Codex of Power, a collection of some of these very same legendary aspects to be used at will proves they understood how important these were. The drop rate of these items and how early on in your leveling process you start seeing them, once again shows an intent in making sure you have the tools you need to make the build you want.

Sooo… what’s up?

What’s up indeed. Why is Blizzard always throwing legendaries our way as an answer to "lack of content" or "lack of incentive". 

My personal guess is: they simply don’t have anything better to offer right now. They hear “we want more incentives to level up” and "we want more content", and they know how to fix it. But all of their solutions take time, a lot of time (game development is long and hard y'all!). And they probably have most of these things laid out on a spreadsheet, assigned to design teams already. But until these are ready, all they have to say is "we'll move that drop rate slider a little to the right, give you more shinny things you already have." 

Now is this the right thing to do? Would they be better off telling us "we're working on it, be patient"? It's not for me to say, I'm no PR staff. But I know one thing: When you say "the treasure goblins are boring", what game designers badly want to answer is "yeah we get it. We'll make cool unique items that drop only from them, and then sometimes when you kill them, you'll anger the Goblin King and he'll spawn somewhere on the map." They just can't always say it.