This is kind of long. Basically it's a dungeon like you would see in any other MMO. Players have roles and to succeed they must stick to them.
3-5 players. Strip everyone of their gear. Everyone picks a class and gets gear based on it: Tank, Healer, DPS, Paladin, or Necromancer.
Tank: High HP, resists/DCI, but no spellbooks.
Mage: High Int, FC/FCR/LMC/LRC, only a Magery book.
DPS: High Stam, HCI, sweet weps, infinite refresh pot, no spellbooks.
Paladin: Support class, medium stats. Based mostly on having a Chiv book; they can DPS (consc wep/EOO) and heal.
Necromancer: Support class, medium stats. Based mostly on having a Necro book; they can DPS and improve the DPS of the group (Corpse Skin/Evil Omen.)
LOOT/PRORESSION:
Players start off with gear that has 50% of the stat cap. As they progress, they get better stuff, capping out just before the final boss or so. Two methods of this: Random/Tiered.
Random: New armor/items are obtained from boss drops. Bosses drop some items, out of a set loot table. Some stuff is armor, some is support stuff (infinite heal pot/arrows/bandies, blank magery spellbook, bulk regs or 100% LRC jewelry, etc.) So maybe the tank gets and upgrade and the DPS gets a new bow. Or a blank book so someone else can start healing, some blank scrolls/inscription tool and a blacksmith hammer (both which suck individually, but can be used hunger games event style to make stuff for the group at certain points.) Or maybe you get a boat, which lets you get a chest somewhere

Tiered: New armor/items are obtained at certain points in the dungeon automatically. So everyone gets a set upgrade at a set time, ensuring everyone improves together. However, this becomes repetitive rather quickly, as after multiple runs people will be accustomed/bored with certain roles potentially... There's only five ways to play on the tiered method, while with the Random progression system, every run through is different. Some might have generous drops and you breeze through, other times you may not get great stuff, or you might need to make due with what you have.
Things to consider...
-Does everyone get bandages? If not, mages/paladins become essential, as they are the only healers AND the only active rezzers.
-Monsters drop bandies, so everyone has a chance, but must use them sparingly. Or DPS/Tank gets some at the start, but not many (to save for rezzing.)
-DPS could get bushi/ninja books
-Tanks start with infinite heal pots?
-Tank needs to keep aggro somehow, but not do more damage than the DPS?
-Restrict weapons to classes? Pallies get maces, tanks get 1handers, DPS have 2handers, mage gets staves, necro gets... daggers? iunno lol
-Split the DPS class. Fighter and Hunter. Fighter uses melee weps, hunter gets a bow and pet summon scrolls. Or a pet. Or just a bow.
-Make some areas easier if you have a paladin/necro in the group, in that some spells are super-effective. Dispel evil to prevent being overrun in rooms with LOTS of enemies. Wither/Holy Light as cold/energy AoE respectively (no cold/energy AoE on any weapons, so casting is encouraged.)
-The Necro could tank with Curse Weapon/Blood Oath... Give them two options when they start? Casting gear or attacking gear, with sword/shield and a nice DPS wep if they wanna switch over.
-Maybe give necros/pallies some magery scrolls, arch cure, mind blast, protection, etc., but no book; OR they can just loot scrolls from corpses.
-Velocity/Balanced Bows. Velocity is like harm, but reverse; the further from a target, the more damage done. Balanced lets you drink potions with a bow in your hand. Give these to the DPS class OR potential hunter class.
Switches that must be activated by players together (think the opening scene of FF7, or like Yoda said, multiple ppl on tiles for the doom lamp.) Small teamwork is required to open a door, but it's mostly just talking/actually having a second person there to progress. Isn't that what we all want?

These were separate ideas from the dungeon, but could be adapted easily:
-Two people in a room, two people overlooking said room from a balcony. Balcony gets stripped of its gear and given caster stuff/spellbooks/regs. Disable cleric spells on the ground AND make mortal strike traps everywhere, so the two on the ground cannot heal themselves. The two on the balcony MUST heal the two downstairs, and maybe do some damage where they can through magery. (Dungeon: Everyone gets MS'd, healer and or pally need to be quick to heal the tank/whoever takes aggro. Or have the Necro tank with blood oath/curse wep.)
-Two bosses, one which takes ONLY cold/energy damage, the other ONLY fire/poison. So each is immune to physical and the elements of it's counterpart. Split the party into two rooms, have them swap back and forth every 30 seconds. Or, ONE boss which changes it's resists mid fight, or the two bosses interchange places until both are dead... No idea where to go from the resist part here hehe, but it makes people either bring a weapon that does that damage type or use magery/other spells. (Dungeon: spells to do energy types, paladin with consec wep, looted/acquired weapons, etc. Could have a previous boss/special monster that drops an item that helps here... Can be a 100% energy/fire/cold/poison weapon, lots of ebolt/lightning/fireball scrolls for one of the party members, or a mortar and pestle and earrings with 500% enh pots for explosion pots, as a really in depth way of defeating the boss
