Hello! Heres my suggestion.
The first of all, its the thing i wish to see in Any ARPG Game
and the idea is basicly "Raiding", a Team-oriented (lets say 4-5ppl) Co-op PvE boss fights that require tactics and are a little more complex.
Fight would focus mostly on doing your role in the group, and doing "Mechanics" instead of blindly DPS'ing and jumping around.
I would split the idea to 4 parts: Roles, Mechanics, Gear and Balance, Theme. And i would give an example of fight/raid from top of my head.

1. First of all, Roles. The traditional Roles in RPG games are allways Tank/DPS/Healer. In Wolcen you can have allmost infinite variety of builds.
   and the main thing i've mention in the begining is "Doing your role" Well with Certain Mechanics you'll need Certain builds to be able to make
   pass them (not forcing builds on players, just specialazied i none way or another).
   With 4-5 people group, if they all are a simple Glass-Cannons, they would take down a boss preaty fast, but they wont survive a 1st spell/mechanic.
   The point of all theese "Roles" is to give oportunity to allmost every player specialized in something specific to "shine" at a boss fight, so we As a
   group of four/five individuals can be prepared for any of the upcoming mechanics, so we can defeat that mighty boss.

2. Mechanics.
   What do i mean when i say mechanics. Mechanics would be the Variety of Spells/Abilities, and Tasks that one or more players would need to complete
   to pass further into the fight, ignoring them not allways would end with wiping whole team or end the fight, but will have hard consequences.
   There can be many types of mechanics: movement, dodging, positioning, soaking, gear-check, environmental and many more. I wont explain every single fo them
   but i'll mention them in example boss fight.

3. Gear and Balance. This is a really wide topic, i'll write only about basics.
   First of all you dont want any specific gear requirements for the fight, but in the same time all-crap gear shouldnt be able to do it.
   And ofcourse gear that drops should be adjusted to your difficulity, which brings me to te Balance.
   Balance based on difficulity is the most common and easy way, example: 10 levels of difficulity each one harder than the other, not only with dmg/hp of
   boss and mobs, but every lets say 2 lvls there a new small mechanic change or new one added that makes it tougher.

4. Theme. Theres not much to talk about, we'll have 3 acts on launch, probabbly all 3 will have diffrent themes. Raids could be easilly Accessable,
   or only throught some extra quests, campaigns, resources like Gold payment, or item find. They can have act theme something related to the story
   or something completly unrelated and new.

Raid example:
Some introduction:
Theeme is placed in act one, on open fields and all those forests, where all the bears and barbarians run around.
You find a Mighty Totem, with no use, you ask someone specific in town, and he tells you a "legend" about mighty shamans vilage, so you decide to
dig deeper into the story. You go to the places mentioned, some small mountains, you find the right spot, use the totem, and bam
you're at the entrance to mighty shaman vilage. Your group enters and just smash alot of trash-mobs (liek you do normally) that attacked you since you're intruders.
Some loud voice tells you to stop, and the boss comes, hes angry, cause you're slaughtering his vilage, he doesnt like it, he measures you with his eyes
and decide that you're just a pawns for him not worth his time since hes the mightiest Shaman the master of Elements a semi-god of some sort.
He summons two elementals while walking away...

Raid fight:
Theres a big Fire and Frost elementals, one of each. If they get near eachother they start to vaporize dealing massive damage to Everyone including them.
Frost Elemental have a really strong freezing aura, slowing all movement/attack/casting speed by 75%.
Fire Elemental burns everyone around, emiting fire nova every 7 seconds, and apply a Burning stack that increases further damage from fire nova by 100%

This is an example of a Gear-check fight, you need to kill them, before they kill you, since every 7 sec dmg is getting higher and higher untill u get 1shoted.
In the same time you're slowed by 75% and you move and attack like a turtle.
You've got to decide which elemental you're killing first, frost one? to get your 100% speed so u can nuke down fire one faster, or ignore frost one and kill
fire one first so you stop the fire nova before it kills you, or maybe kill both of them on same time? Or bring them closer to eachother carefully
for a while so they vaporize a little, as much as you all can handle.

You defeat that boss grab a loot, and go further, there are few more bosses to kill before you get to might shaman, and he decides to fight you.

Shaman mechanics:

Phase 1 Shaman gets infused with lightening 100%-85% of HP:
- Lightening spell, Calls down a massive lightening on the ground, that Shocks player who gets hit, if noone get hit, lightening hist the ground,
and all players are shocked shocked players get 100% dmg from next lightening strike. (a soaking mechanic)

Phase 2 Shaman gets infused with Fire 85%-70% of HP:
- Fire shield, deals fire damage to atackers.
- Fire spell, targets a random player (not frozen one) burns him and all enemies withing 5 meters for X dmg every second for 10 seconds, if you stand near frozen
targets for 2 seconds, ice melts and they get unfrozen. (moving and position mechanics)

Phase 3 Shaman gets infused with Frost 70%-55% of HP:
- Frost shield, hitting with meele attacks slows the attacker for 25%
- Frost spell, targets a random player, and forms and icycle that deals moderate ammount of frost dmg, and also freezes a target permamently.

Phase 4 Shaman gets infused with Earth 55%-40%% of HP
- Earth shield - gets 25% reduced damage.
- Earth spell, Throws a big mighty boulder in random place, boulder will shake the ground and stun everyone for 10 second, if player gets
hitted by the boulder directly, only the player is stunned. (soaking)

Phase 5 Shaman gets infused with all elements above 40%-0% of HP:
All of above!

You need to Free frozen people when you burn, you all need to share to soak lightening attacks so you wont get 1 shoted, someone needs to grab that boulder so others dnt get stunned. its an example of really simple fight, there can be more complex fights :)

The example is just from top of my head for people to better understand raid.
Tell me what you think, and would you be intrested in doing hard-level content like this in group of 4-5 people?
I think it could be intresting to see this kinda of Raids in ARPG game.