Now with Diablo 4 those limitations are gone and a massively improved trading system is possible, but unfortunately it sounds like we aren't getting anything close to that. Instead, we're getting Smart Loot and limited trading, which to me screams a lack of understanding of what made Diablo 2 so great in the first place. How can you make a game that is entirely about loot and cut out TRADING? It blows me away, it's like removing the jumping mechanic from Mario, or getting rid of the demons from Doom, I don't understand a design choice like this.
If you played Diablo III before RoS it is kind of obvious why. This is also why a lot of games do not allow trading, while the ones that do are degenerate for it or expect to make money from it.
Basically robots ran rampant farming loot for trade on the AH, RMAH and third party sites. When cheat detection finally had those under control the companies moved to using cheap/forced labour from third world countries instead of robots to farm loot. All the best gear ended up in speculator hands which then sold it off to rich kids on third party websites where such high end loot was selling for over $500 a piece. Normal players could not get any good gear because to try and make an economy the drop chances were kept low so self-finding was not possible. Then there were all the hackers trying to gain access to players accounts so they can empty them of all their hard earned loot and flog the stuff off for real money using third party websites before the original owner could recover it.
When WoW and D3 removed trading of late game gear account hacks, phishing and advertisement attacks dropped massively across BattleNet. Normal players could also progress in D3 since drop rates were buffed and smart loot added. Most Diablo III players from the time liked the change since they fell into the "normal" players who were not pay to win so struggled to progress.
Smart Loot also tells me that the item system itself is going to suck. They'll use the same horrible system that was used in Diablo 3 with primary attributes and a severe lack of affix variety. Items will be unbalanced and most items won't have a purpose besides scrap material (puke). I have a hunch that the reason they renamed Unique items to Legendary in Diablo 3 was because they were admitting that there was nothing unique about them. It was almost like a Freudian slip or something.
The itemisation changes to Diablo III were made very late in development. When I was playing the invite only beta the items initially were much more Diablo II like and even changed every 2 weeks or so. This is also why attributes like single resistances and element damage types were kind of pointless and deprecated since no monsters really used immunity (expect 1 in RoS which was added as an Easter Egg to literally be Immune to Fire in reference to Diablo II) and elements being a parallel armor meant that all resistances had more value as it literally acted as armor to reduce damage.
Itemisation as a concept is very difficult as you need a fixed sort of progression otherwise you end up in the silly Diablo II situation where until you create 1 of the few viable late game items you are using some cheap shop brought wand or staff because it is infinitely more available and better than all those "unique" wands and staffs that drop because it gives you useful skill rolls. Diablo III kind of fixed this during RoS and was doing well until stat inflation caused everything to become a loot explosion of legendary tier items.
1) Cut the number of item affixes in half (if not more).
As mentioned above this happened late during development just before release. Items had a ton of affixes including bonuses to skills, bonuses to spell damage, on attack/hit effects e.t.c. until then. I suspect they just cut most of the "useless" affixes since otherwise that is basically artificial padding.
2) Added primary attributes to classes which were needed in order to deal damage. If an item didn't have your primary attribute then it was automatically trash.
Again this was done very late into the development of Diablo III during the beta testing. Originally the Wizard class abilities relied entirely on item affixes for scaling as they were not based on weapon damage or primary attribute. Primary attributes did not exist with each level up granting you a variety of different attributes (Attack, Precision, Defence and Vitality). The ratio of the stats was likely class specific and that likely was involved in choosing the different primary attributes for the classes.
I suspect those original attributes were dropped because logic dictates that the only good one is attack. More damage is always better. Hence they needed to tie the same damage scaling to every class and so adopted a Warcraft III style primary attribute system to raise damage. This also tied into all abilities being made to scale from "attack damage" rather than their own scaling systems to help progression and not make the rolls of your spell damage buff on your items carry you no matter how low quality the items are.
3) Made Unique affixes a billion times better than anything you could find on a non-Unique item. RIP item variety.
4) Failed to make non-Unique items roll more powerful affixes which would allow them to differentiate from one another.
This only happened during RoS when unique items were given basic affix rolls that are larger than what rare items could obtain. This was to give purpose to unique items since at release unique items were mostly useless due to not scaling to level and rare items entirely dominated the meta. In the run up to RoS the first legendary overhaul made some items, like Skorn, worth using but still the meta was very much dominated by rare items.
This change was to give clear item progression with legendary and set items being the best, as they were also the most rare. This worked well during early RoS since they were still actually quite rare to find. However as stat inflation happened enemies started exploding them everywhere to the point that yellow items were nothing more than annoying screen clutter.
The insane legendary affixes we have now of +100,000% blah are just a result of stat inflation. Instead of nerfing to keep everything around a "normal" they decided to keep buffing everything until now numbers are meaningless and you either one shot enemies or never can kill them.
5) Removed any need for Normal/Magic items by scrapping Runewords and most crafting options.
This was one way they could have taken the meta. However as Diablo II showed you either end up with the best in slot being a rune word, or a unique item with a few exceptions where a magic wand offers better skills.
They just got done remastering D2 for fucks sake so why the lazy design choices?
Blame the Diablo III maintainers for deciding to keep adding 0s onto the end of everything. Originally the item sets added like +50% whirlwind damage but because they accidently made another set OP they had to keep adding 0s until they all ended up at around the same GR tier. I mean they could have nerfed the other classes to lower their maximum GR tier but I guess "big numbers good".
I just hope there is some sort of PvP aspect as that should at least force them to try and keep numbers sane. Instead of a Wizard being able to OHKO the tankiest player 10,000 times per hit...