Level 67 and my dopamine is wearing off, things I'd really like to see them improve:
Be more punishing for deaths.
Death don't really matter currently, outside of nightmare dungeons (where you can only revive X times). I personally like the extra challenge dark souls give with this.
PVP leaderboard, K/D ratio's, 1v1, 2v2, zone domination etc.
Lot of potential here for more endgame fun
Make doing more difficult content more rewarding
Currently everything is geared towards farming efficiently and easily, which is simply boring, making the content very hard is where the fun is, however you should not do this currently as it's very inefficient.
For example, when I was level 60, I'd fight level 73+ mobs, that was a lot of fun and challenging, but the game punishes this behaviour.
More exciting skills, gear and builds
Compared to something like Elden Ring, the skills are quite flat and boring, they play it very safe. The same for the gear.
Uniques suck, make them better
There is one unique I can use, the rest are horrible.
Add a gem tier
Add a tier above flawless that would take like 50 flawless to create.
Add gear to the horse
Rare gear that can improve the speed, or the stamina, etc. More dopamine hits.
The open world was OK I guess, but I realised that with a top down view like Diablo you can never appreciate an open world fully like you can do in a third person. Where in Elden Ring it would feel like adventure and I would stop in awe of the vista's, here you simply move on from A to B.