TLDR Season 5:
Has a memory leak, going up to 6gigs of ram, and locks up within 1 minute, requiring an end process tree in task manager to exit. I cannot recommend this game. Season 4 was amazing, 5 is a dumpster fire.

Legacy Review Pre-Season 4:
Diablo 4 didn't respect my time so I'll keep this short and sum up the main points to decide if this is the game for you:

I got 100% in the game. This is truly a bells and whistles mobile game with as bare game play as is required to reel consumers in. Events are just color changes for enemies/regions, everything else is 100% identical. Aside from the end-game boss loot targeting, there still isn't anything else as mentioned.

- Fun, basic gameplay, with a boring gameplay loop that lacks dopamine hits.
*Each class has 4 builds which can be mix and matched.
*Sacred Ancestral Unique gear only matches some builds.
*Corpses have a small max limit for 2023, damaging two specific builds.
*Forgetful, throwaway music, but is good nonetheless and gets the job 'done.'
*Gameplay feels over a decade behind the times, lacks innovation.
*Inscribing items is the exact same function as the Horadric Cube.
*Enchanting items is 5 steps backwards in this game. You can't see what you can change on the affix until you've spent your material and you can't refund them if you choose no affix.
*All Armor Sets (Green) were removed and sold in the Shop (with no bonus).
*All cool armor & weapon effects from epic sets in past games or even Path of Exile, $. Not a single one for free. Not one.
*Archon, Boneweave, and Sovereign armor sets are 99% identical, most sets look pretty similar as well to goad you into the shop.
*Game freezes on occasion when loading near other players (when streaming them in).

- Feels like the game was made by people who don't play video games.
*Always something to do, but always lacking dopamine hits, i.e., the loot is only ever incrementally good except when first accessing a new world difficulty tier.
*Altars of Lilith can be completely ignored unless min/maxing as the upgrades give mathematical negative returns almost immediately, regardless of the level scaling.
*Mining Ores and doing Herbalism (you just click the deposit/herb, then pick up the item) is required to upgrade Gear and Potions, respectively.
*PvP is both Optional (open mouse wheel -> scroll right -> apply Blood Mark) even in the 2 PvP areas and broken due to a flat '92% damage reduction buff,' which means if you did 5,000 damage now you do 400 (8 x 5000) / 100 , so you still kill someone in 1-3 seconds depending on your class and theirs.
*PvP marked for blood (enables pvp) can glitch out, preventing you from attacking others but enabling them to attack you (when the glitch occurs, you will not have the particle effect so you won't even know). When glitched you must logout to remove the mark.
*PvP is markedly unfinished and poorly thought out, you can reduce pvp damage further by 30% for 20 seconds, but this requires cutting your screen in half with your inventory, then clicking on a tiny box (all mid-battle most likely), then right clicking on a scroll.
*PvP is unbalanced for every class and every build, each fight lasting a second, maybe two.
*I enjoyed the 'Open World' aspect. From a 3D Designer point of view, it isn't really open world, they simply took 5 Acts of areas and stitched them together, removing the loading screen and mostly hand-crafting the over-world. When taken in this way, the world map isn't really that big, and we loved this, even if it creates a lack of cohesion for the player from a world building perspective (i.e., you can cross Estuar in minutes).
*Minus copy paste 'special' bosses to climb the season chapters (which I didn't finish), you have Helltides (Tier 3/4) for targeting loot, Obols (all tiers/from events) for targeting loot, and Nightmare Dungeons (Tier 3/4) for upgrading Paragon board sigils (same function as upgrading gems at the end of a D3 Greater Rift).
*Season and in-game content builds on Diablo Immortal, for better or worse, i.e., to complete the Season 2 content, you have to climb to Tier 3 at the least.
*The loot you get is the same everywhere, nothing has a specific loot table, minus first time kill rewards, for example, Echo of Lilith.
*Tired, boring, cliched, copy-paste story line, trying to be something it's not. Loved Lilith, hated the plot existing to move me from A to B.
*Hitting enemies lacks responsive feedback, they just jitter slightly, flash white/silver, or fight right through it.
*Sounds of hitting enemies with the physical weapons is lackluster.
*Boring, copy paste Affixes for gear.
*Great side quests; Horrible voice acting outside the Main Quest. Shameful, especially horrendous as I played Baldur's Gate 3 for 181 hours before this game so it stuck out like a sore thumb.

- Store front with skins priced at $38.41 CAD after tax for 1 cosmetic armor set.
*Horse armor selling for $23.14 after tax, and WE ALL complained about Bethesda, hah!
*Prices normalized by American Companies & Consumers, pressured and forced onto everyone else due to how the global currency exchange works and has functioned for generations; some companies eat this exchange to increase spending in lower GDP countries, see Fatshark with Warhammer 40,000: Darktide, which eats roughly 56% of the conversion rate for the consumer, and this is but one alternative method of targeted pricing as there are many profitable ways to go about this.
*No 'Statistics' based research has been used (mathematically even if less than 0.1% buy macrotransactions from Diablo 4's store, they make Real Profit), no transparency between professionals and corporations, every game with MTX stores share the same pricing, same scheme, except D4's store lacks 'FOMO' or, Fear of Missing Out, i.e., the shop lacks items and will rotate every item every 24 hours, some into the same slot, some down to the bottom, some up to the recommended. If you feel inclined to buy, just wait, you will never lose out and they never remove items from the shop.
*Game that has soft-lock issues where not enough enemies spawn carrying Animus on occasion.
*Waiting in queue indefinitely, soft-locking in queue, login soft-lock.
*Item windows and comparison windows constantly flash on occasion (appear and disappear) with no apparent fix or cause.
*Enemies die standing up and their model doesn't disappear. Haven't seen any T-posing, they just die with their idle animation active until you log out. Happens frequently in the Blood Harvest seasonal event.

Made it to level 54 HC Necro, 70 SC Necro Tier4, Lack of dopamine in Helltides, World Loot is God Loot, Same Dungeon Spam.
Completed exactly 5.5 Chapters of the season journey.
Got bored looking at all the copy paste armor sets in the 'free' game.
Didn't buy any Macrotransactions:
People listen, I'm in Sociology, I do Statistics, I love Math & Logic, and these are *not* microtransactions.
Micro = small
Macro = large
$5 USD or $7 CAD would be a microtransaction in this case.
When the transaction is half or 2/3 or 3/4 the price of a video game, this is called a macrotransaction.
This game has macrotransactions, there are no microtransactions in the store.

It's an egregious business model and I have deleted all my characters and uninstalled.
I can't recommend the game even though I sometimes enjoyed my time with it because there is only so much abuse consumers can and should take before looking to invest their hard earned disposable income elsewhere.

These are just my subjective ramblings of this 40 year old.
You decide if it's for you in the long run.
Oh, and wait for a sale if you want to buy, the game is frequently on sale for -40% off.
Enjoy @everyone!