Very excited. Quin69 had around 30m to interview one of the two lead game designers of Diablo 4, Joe Shely. Here's a very rough translation of the questions and answers:
Paragon Levels? A replacement system for them, they liked what it allowed (30-60m sessions that progressed character at cap).
Endgame? Lots of different activities, such as world bosses, key dungeons (variation on greater rifts, scales up past player capability), and other systems Not Yet In.
Max Level? 40 - subject to change.
Solo-Self Found Setting? No.
Leaderboards? Yes, need to be meaningful, around specific activities (design philosophy more around challenge rift leaderboards from D3).
Trading? Yes, no AH ingame. Game philosophy is major source of item upgrades to come from killing monsters - trading to supplement that. Current development has three tiers of items; freely tradeable (e.g. crafting mats), tradeable once (crafted or regular gear), and untradeable (best items ingame, bind-on-pickup).]
Crafting? Under development, endgame is focused around item modification where crafting is core.
Seasons? There will be Seasons, each season will have the most powerful items swapped to shake up meta.
Talent Trees: Looking for Feedback, current tree shown is the development tree being used.
Skills: Modified (sometimes extensively) through legendary items, also as you level you gain skill points that unlock and level up skills. Cannot be respecced - there are tomes available in the world to earn more points.
Itemization? Greys to Whites to Blues to Yellows to Greens (sets) to Legendaries, Sets only as powerful as low level legendaries.
Monetization? Base game & expansions core for flat cost, with cosmetic cash transactions available.
Player Housing? Interesting idea, nothing to announce currently.
Addon Support? Nothing to announce, feel that things like DPS meters generally just make people feel bad.
Keybind Philosophy? Built from the ground up that everything is customizable, everything can be changed to suit the character and playstyle you want.
Anti-Cheat? "High importance item for us that the game is pure and the experience is fair" (Frag: I hear "We're seriously serious about it this time guys!")
Timeline: Not coming soon, not even Blizzard Soon.
Here's the
link to the stream, interview starts around 1:28:25.
Edit - 11/2/19
Couple slides from today's Systems & Features Panel:
(More) Runes, also during the panel they mentioned they're looking into a scaling/progression system for runes:
Loot progression slide:
Hardcore Diablo 1/2/3/4 & Retail/Classic WoW adventurer.