https://us.diablo3.com/en/blog/23189677/diablo-iv-feature-overview-11-2-2019

Barbarians will be able to haul around four total weapons and swap between them dynamically at any time. You’ll also be able to assign specific weapons to different skills, allowing advanced players even greater depths of customization.

Sorceress will be able to control and dominate enemies with a new Chilling mechanic. The more Cold damage you deal, the more foes will be slowed, frozen, and eventually shattered by your attacks.

Skill Points will be earned by leveling up as well as by hunting down rare tomes out in the world.

Unlike previous Diablo games, Diablo IV is fully open world. This means you can explore any of the five distinct regions in any order, at any time, and travel seamlessly between them. With introductions like monster ecologies tied to regions, a shared player world with public events, and town points of interest that act as social hubs, Diablo IV will feel a little less lonely (though no less bleak).

While most of the world is socially open, certain, smaller parts of each region are campaign specific. Once the campaign objectives have been completed, those areas will also dynamically open to other players. This means you might see another party of adventurers pass you by or you could organically stumble into an event or World Boss other players are already battling.

Affixes work a little differently this time around. While you’ll still see expected effects like Molten, you might be surprised at how the Multishot affix changes up strategic gameplay depending on which enemy it affects.

A Multishot enchanted ranged Fallen might throw three projectiles at you, as you’d probably expect. Put that Multishot enchantment on a Fallen Shaman, though, and your priorities change as he begins to revive three of his friends at a time instead of just one.

Normal -> Magic -> Rare -> Legendary/Set -> Ancient -> Mythic
In Diablo IV, we want Legendaries to be just as, if not more, powerful than Set items. We don’t want you to feel beholden to one particular class set to play your chosen style. Ancient items are a system we’ll be leveraging for Seasons, but we’ll dig into that at a later date. As for Mythic items, these will be so powerful you’ll only be able to equip one of them at a time, so choose wisely!

When it comes to combat statistics, we’ve simplified the math problem.)))
Some items will also boost individual Talents, effectively acting as bonus points spent in them. If you want to go all-in on Pulverize, you can do so with Skills, Talents, and items!

Legendary Powers (типа руны для скиллов)
Legendaries should fundamentally change the gameplay of abilities, and that’s exactly the approach we’re taking in Diablo IV. The best way to illustrate this is to review a few powers we’ve worked on for the Sorceress skill Teleport.
One Legendary might increase your defense shortly after you Teleport, making it a great defensive escape tool. Another might increase your damage for a short period of time after you Teleport, making you more likely to want to jump into the fray. Still another removes the Teleport cooldown entirely, but now sends you in a random direction, so you have high, but unpredictable mobility. Lastly, we have a power that adds a burst of area damage to enemies upon your arrival.
Combining all these Legendaries can result in some pretty wild and satisfying results, and it’s up to you (and perhaps a little luck) to decide which ones to combine.

Runes
Runes are back and better than ever! Runes in Diablo IV translate to another layer of gear customization. They come in two types: Conditions and Effects. It’s as easy as socketing in one Condition and one Effect to create your own Legendary power. There will be a great variety of both types of Runes and we can’t wait to see what sorts of combinations you come up with.