As a long time Diablo fan, I really want to see this game succeed.
While I feel I can provide feedback on many aspects of the game, I can see many of my thoughts have already been said by members of the community. As well as considered by the very communicative Diablo IV team.
This brings me to an area that itches me more than others; The art and design.
As someone who’s invested deeply in visual communication, I want to share the way I feel about the current UI of Diablo IV as there’s much to talk about.
I want to start by showing you this image:
https://i.imgur.com/u7fXHcc.jpg
This is a screenshot of MrLlamaSC tilting his head sideways as he tries to read the vertically placed skill category names during the demo 
Now, don’t get me wrong! I feel like there’s a lot of good to be said on the UI. The assets are some of the most beautiful I’ve ever seen in a video game. But considering how amazing the in-game look is, I feel like the UI/UX is not up to par.
Disclaimer: This is all just one man’s opinion! I do not claim to know better than the development team. I’m just sharing my thoughts based on what was shown in the demo. I understand most of it subject to change.
Here are some points to consider:
Interface materials’ thematical accuracy (mostly positive):
https://i.imgur.com/z8DPHix.jpg
Diablo’s UI has always been as dark and gothic as everything else in it. In Diablo I and II we saw interface panels made of stone, with the information carved into them. They also had trims of metal in them, ornaments that brace the information and make a grid. Diablo’s UI is truly a gothic church.
Diablo III also introduced stained glass as decoration and the use of other materials. In the inventory, paper was used for the “paper doll” and leather was used for the item grid to connote bags.
I see a lot of that coming back to Diablo IV and it’s great. Stained glass art for skill icon means they can “light up” as if light is passing through the glass when they’re active (which I would like to see more of). The skills you gain show up on paper and traits are being set in stone! They even have the traits’ path flow the same way the blood was flowing on the altar in the cinematic trailer! Wow!
Also, in areas where the logs cover the player (like in the social tab), a slight transparency is allowed so you can see a little of what’s going on in-game. I think the same should be done for an empty health / resource globe, where it makes sense. In the edge of the character tab it doesn’t feel as right.
The edgy, dark metal trims that surround the tabs are beautiful! A little overdone in some places like the game cursor or around the health globe, but it generally fits the tone of the game.
In contrast, the diabolical diagrams within the background of the skills tab, the traits tab, and the health / resource globes seem forced, unnecessary and a little cheesy. It’s kind of like stock art was placed to make the tabs seem less empty instead of distributing the information differently or creating new diagrams that complement the flow of information. Diagrams are usually used to display information, not to decorate. Maybe the information itself can be placed in a ritualistic diagram manner?
Another thing to point out is that the overall color value of the paper tab is on a much higher key range than the stone tab. Information on the skills tab seem to pop out while information on the traits tab seem to not pop out as much.
I would also like to see the gargoyle next to the globes interacting with them in some way (like the way he held the globe in the first two games) and not just sitting there.
As well as the red health liquid projecting a bit of red light onto gargoyle. Imagine if the already realistic and physical looking UI elements were affected by the light and shade of other UI elements?
Typography and distribution of information (mostly negative):
https://i.imgur.com/7b25tHz.jpg
This is something that went well with Diablo III and I would like to see Diablo IV take note from that.
The hierarchy and readability of the UI in general could use some work. I don’t know how much they tried with this one, because a lot of the information is subject to change, and typography takes a lot of time and work to perfect. So yeah, maybe it’s obvious, but I’ll point it out anyways.
The typography of this demo continues to haunt me. Tabs always starts with a different looking title. There I find texts of different shapes and sizes. Words choked with outlines and drop-shadow. Unreadable vertical headers. I witness senseless font usage. Serif against san serif. Bright brown backgrounds for pop up tabs. And then, weird text justifications. Unnecessary icons. It burns my eyes. Break my grids. I wake in terror at the thought of it…
I’ll just leave it at that. It’s the thing that stood out the most to me and it really needs fixing.
User experience, navigation and management decisions (mixed):
https://i.imgur.com/dc0ykKt.jpg
I’m not going to push too hard on the Tetris inventory from Diablo I / II, I get why some people don’t like it. But didn’t Diablo III already solve this issue with 1x1 for small and 2x1 for big items? An armor and a ring cannot take the same amount of space! Unless we’re going the World of Warcraft way (1 size fits all and everything is a square icon). Right now, it seems like the design is trying to have the cake and eat it too
I still think that managing big item graphics in the inventory creates a more intimate experience that’s grounded in the reality of adventuring. Small item icons make them seem less important than they are. Show us those beautiful item graphics that your team created! They really look great. I can’t imagine those tiny icons with more than 2 sockets in them either.
Character tabs (Inventory, Skills, Traits) and Game tabs (Map & Journal, Social, Game) are properly separated. They also seem easy to navigate. The exception from what I’ve noticed, is the inventory which has a scroll down bar on the left! Most of the people I saw play the game didn’t even notice it. I would much rather have different category of items separated into clickable tabs, the same way everything else is. Scrolling down is very out of place.
Regarding the gameplay UI; I’m fine with breaking from the symmetrical health / resource globes being on each side of the screen. This creates two evenly sized clusters on the bottom left and top right sides of the screen. It also doesn’t come in the way of the character tabs, which is great.
Combat user interface (mixed):
https://i.imgur.com/gS2gjEE.jpg
My favorite thing is the little icons that imply boss modifiers, like cold enchanted or shadow enchanted! It’s visual communication at it’s finest. In the previous games, by the time you read “Cursed, Extra Strong, Fire Enchanted”, you were already dead. So that’s a huge plus!
I’m also happy to see there’s no overlaying map to cover up the combat. Keep the mini map going, it’s not that hard to get used to.
The rest of it is a little uninventive. Maybe monsters’ health can also be a round globe? Maybe monsters’ names can be inside their health bar to make it more readable and take up less space. I think more effort should be made to keep the combat area clean from UI as much as possible. This includes monster levels, the flashes that appear when you hit them and the floating numbers that pop out of them.
I also noticed that elites don’t have much to make them look elite, like a fancy health bar or text. Only world bosses have those.
Okay. I’m done. Please share your thought 
At the very least make the items bigger.
Thank you again for your time!
