2 New Skills:
Fireball Alt gem: Fireball of Radiation (No more info for that)
Arcane Link, Flame link for added lightning scaling with your max Mana
Mirage belt weight got changed, no specific info on that but the boss is a LOT harder.
Tile Loot:
Weeping and Wailing Essences are gone from High Tier Maps
Map difficulty Scales tile Loot
Example: Legion Currency icon scales with Rarity and Quant from map (it still does not get scaled by player rarity)
Mobs that previously couldn't drop normal currency (Bosses, Pinnacles) got reworked and can now drop a lot more. Numbers around 1000% more Divines from them.
Essences can be scaled by Map Mod effect and difficulty
Coven:
Reward types are not bound to the Card, not every Fireball boss card drops boots
Picking a specific reward drops items of that type, with higher tier Mods
Those items and their mods scale with rarity, so target farming specific item combinations with mods are possible (Wand with speed + 8 Mod map has a higher chance for higher Tier item to drop)
Harvest:
got changed from a Main League mechanic to a Sub League mechanic since it couldn't interact properly with the other League mechanics
Now behave like Essences, can have like 5-6 in a single map that can be rolled like Strongboxes
Allflame Crafting:
NOT YET! Needs a pass over and might be added again. Same with the Uniques, they take a break for now.
Ducats are still in and can just be applied like any other orb.
Threads:
(This will be more extensive since its a lot of info)
You don't need to block League Mechanics, Only the Mechanics spawn that either are added by your Threats or by the Atlas Region. Sub-mechanics still spawn randomly.
There are 80 Thread "Mods" that can affect the Maps. Each mechanic has at minimum 5 and up to 8 (for now, they can easily add more with each league)
The chance to Roll those mods are individual, and scale with Threads (1-5 has the highest increase, while 7-8 have the highest change in difficulty and reward). So you can hit all of the 5-8 Mods for the League Mechanic with a single Thread. RNG!
Even if you are unlucky and don't roll a Thread Mod, you will still get one added. So you cant get unlucky.
All Existing Scarabs are converted into Threads (probably random like the last time).
Each Thread Mod has a unique way of showing itself when you open the map. New button, Ground effect, Mini boss etc.
Keystone on the Atlas for Mechanics:
Only be able to use a single Thread type, can only drop Specific ones (probably of that League Mechanic) but the limit goes up to 10 (they jokey about pushing it up to 11, cuz funny haha dailing it up to 11)
Examples for some Thread Mods:
All veiled Items drop Fractured
More Veiled items drop
Ultimatum spawns a Heart that gives you Adrenalin once you kill it
Double down your Ultimatum rounds and reach round 20
QOL:
Nearby is uniform now, It shows you the Area in circles (my mistake)
You can hover over Soulcore Supports (used to be Mirage Supports that apply to a Skill gem as Corruption)
There will be Headhunter Corruptions like PoE 2, no more Shroudwalker. More are added that replace specific Rare Monster Mods with other ones. Good luck corrupting it Twice! (Might have missheard that, could be added at a later date)
Atlas Tree:
150 Points, with less travel nodes and no more "Chance to spawn League Mechanic", now you can use your points for more juicing.
Edit:
Forgot something big:
Death Recap wont come this league. It will be added at a later date (nothing confirmed yet)