I am going to solely focus on things I feel are lacking or bad. I know that this isn’t the greatest way to give feedback, but I think highlighting the things that make me hesitant to purchase the game are the most important things.
General
The biggest problem and issue going forward is skill balance and itemization. Taking D3’s itemization without the flexibility of free respecs is a bad system. I think the goal should be that any Core skill can be maxed and be the primary damage source (presuming the weapon is kept up to date) for a class up to level 50 regardless of legendary item drops. Currently some skills are completely non-viable without certain items. Damage needs to be shifted away from items and into the skill tree, while items should focus on diversifying gameplay. The leveling experience needs to be enjoyable, and praying for specific drops for a smooth experience is not that. Legendarys while leveling to 50 should be fun, not essential. The most glaring example for me is Tornado on the Druid. Homing should be the first node, and extra Tornado spawns should be an item affix.
There needs to be some sort of loot filter. I think it should be so that it makes anything not meeting the specifications you set is automatically marked as Trash in your inventory. This makes cleaning up inventory space so much less time consuming. Currently marking items as Trash feels useless. This would actually make the feature feel good.
In that same vein items need better readability. It is really hard to compare items when the affixes are constantly in different places. There needs to be a clear order of operations to make comparing items easier.
It is really hard to find infomation in the game. There is no Beastiary or equivalent that helps me learn about the systems. I generally just have to hope I get lucky with a loading screen to learn some of the mechanics, and if I load to fast to read it I’m just out of luck. There should be an in-game system for researching game mechanics.
Character stats should be prioritized over materials. I also think there are too many affixes that make the whole section overwhelming. Having bleed and shadow damage over time is just overkill. Just narrow it down to boosting damage over time to make things cleaner.
Backtracking in dungeons isn’t fun. I don’t think the layouts need to be changed as much as we need markers showing where the end of the dungeon are. D3 put this in and it was a very appreciated QOL adjustment. All we need to know is what the main path is to make sure we are knocking off the side rooms with objectives in them.
Dialogue too often goes at a snail’s pace. The voice acting is good, but some of the pauses between characters are absurdly long to the point where I’m wondering if the sequence has ended, or the lines just need to be sped up 20%. Barring that all blue quests need skippable dialogue. Going through it one or two times is fine, but I am going to actively avoid blue quests if I have to sit through a minute of talking for the fifth time.
Gem storage feels bad. They take up too much space. They need to go in a different tab.
I am very worried that the gold economy is poorly balanced. A lot of nickle and diming as well as having huge gold sinks. I feel like I am going to be afraid to spend anything but affix swapping gear. Selling gear seems to be the only way to make money, but we also may need to salvage that gear for mats. It seems like gold or mats is going to be in too short of supply. I like earning those things, but stressing out about managing expenses is not what I would call an enjoyable video game experience.
Locking abilities to only 6 feels bad. It made more sense in D3 when we had access to everything. In D4 that isn’t possible with having to invest skill points, but getting items that give one point in skills that you want, but can’t afford to invest skill points into, and having that be a useless item affix feels bad.
Gameplay seems unfairly skewed towards group play. Felt like I was getting higher level item drops in addition to the extra exp, and groups being able to do objectives faster.
Group play needs a more streamlined way to teleport to members. Having to go to town and click a portal isn’t good, and just makes the town more of a lagfest.
Item level drops being ~8 levels lower than your character feels very strange. Giving an alt a couple of weapons that actually match their level makes them a god. I haven’t tested it, but I feel like groups could use that mechanic to have lower level characters carry higher level characters.
Druid
I spent the vast majority of my time playing Druid. Here are the specific things I have problems with for that class.
Basic skills are poorly balanced. Probably need a blanket +5 Spirit Generated for each skill. Maybe +10 for Earth Spike. Storm Strike feels the best because it gives the most Spirit and also procs useful status effects. The others need to be elevated to that level.
I also think base Spirit should be 150 instead of 100. Being able to bank power against weaker enemies to then use against the heavier hitters would make the class feel better.
Too long of cast times on too many abilities make the class feel clunky. This is especially true with how inputs get buffered. I have to be very meticulous with my clicks or I get stuck using the wrong ability, which then makes me click that skill more out of frustration/panic, and can lead to the same problem happening multiple times.
Lightning Storm damage feels bad for single target. It can seemingly miss completely even when fully stacked due to the randomness of the strikes.
Companions need a large damage buff, and the item affixes that give them damage need to be adjusted accordingly. They shouldn’t be useless without items. Vine Creeper may be fine, but the other two need significant base buffs.
Boulder needs to have a boss mechanic. Passing through bosses and doing almost no damage feels awful.
Druid needs more mobility. Being able to efficiently farm is a very important class feature, and Druid’s lack of movement options make me think they will always lag behind in loot/hour.
The Landslide sound effect is bad. Sounds like a potion being used to me.
Poison feels underwhelming. Good against trash mobs, but anything with higher HP doesn’t feel all that noticeable. Also, Rabies doesn’t have good visuals. I can’t tell if it is spreading.
There are the bones of an excellent game here, but some of the systems need to be properly recalibrated to fulfill the promise this game has to offer. It feels like it is in a better place than when D3 started out, but still lacking a genre defining feel.