We will go through some features coming in Diablo 4, which are pretty surprisingly different from Diablo 2 and Diablo 3.
No Set Items
There are no set items in Diablo 4. This is one of the biggest surprises, as we know how large set items are in building a character and feeling a sense of completion and accomplishment in any Blizzard game where set items have existed.
Although set items won't be in the game when Diablo 4 is at launch, Blizzard plans to add them in the future, which is still kind of shocking for most players. When the game's director Joe Shely was asked why set items would not be in the game at launch, he responded that Diablo 4 would omit set items at launch because it's a matter of getting them right.
It's definitely a bit disappointing because the set items are amazing if you have done well. In Diablo 2 and 3, there were set items that you could get at a low level and enhance your gameplay a lot. Whether it was the Angelic set in Diablo 2 for your Melee character or Cain's items in Diablo 3 to level faster, collecting set items and getting two pieces of bonuses is an amazing feeling.
Every Item Takes Up the Same Amount of Space in the Inventory
In Diablo 4, every item takes up the same amount of space in the inventory. Even rings and amulets take up the same size spots. This is a departure from Diablo 2 and Diablo 3.
Most items in Diablo 3 took up two inventory spots except rings, gems, and amulets. But in Diablo 4, it looks like every single item takes up a single inventory space. It is the same with World of Warcraft, where every single item, regardless of size, takes up a single inventory space.
This is a big difference from Diablo 2, where you could feel the weight of an item by the amount of space. In Diablo 2, large two-handed weapons take up a lot of space, and even a one-handed sword could also take up an amount of space. So if we would arrange spaces for new items fitting in Diablo 2, this is like playing the game of eliminating Tetris in your inventory. Instead, in Diablo 4, everything will fit perfectly without any intervention needed by the player.
No Paladin or Crusader Class
There is no Paladin or Crusader class in Diablo 4. But it has Barbarian, Druid, Necromancer, Rogue, and Sorcerer. The hero classes different from Diablo 2 and Diablo 3 will bring us a new world to annihilate hordes of enemies with different skills of the special class.
Open World
Diablo 4 will feature an open world where you will encounter other players and progress through the storyline in a non-linear way. In previous Diablo games, the plot was linear and structured in terms of acts, and you needed to progress through the game act by act. Diablo 3 had Adventure Mode, which broke away from this linear progression, but Diablo 4 takes it a step further with not only non-linear progression but also encountering other players in the open world, finding events to participate in dungeons and side-quests.
World Bosses
World bosses are a new concept in Diablo 4 - bosses that will randomly spawn in the open world and require many players to come together to defeat. When the boss spawns, you will be prompted to join the event. They're massive demons or monsters that the camera pans out to see entirely on your screen. Upon launch in June this year, the game will have three world bosses.
Ashava, the pestilent, looks almost like a winged dragon, and she occasionally breathes green poison on players.
Treasure Beast looks somewhat similar to the Siegebreaker beast in diablo 3.
The third boss is still unknown what it is until now.