Dungeons A True Challenge

Here's a few ideas:
Location of the dungeon: Light Realm, The Nether, (can't unless it's changed), or wherever the hell Bob's Reincarnation is.
Room 1: A large boss arena type room with turrets which spam arrow storm, and a few 10k health mobs which are entirely resistant to one element. You would need to acquire 5 tokens per group of players. After the first room, the dungeon would split into four passages, based on movement challenges for each class. At the end of these, all four buttons at the end of these passages must be pressed before continuing.
MiniBoss: A ranged mob that would shoot an instakill arrow every 1 second. There would be activateable pillars to provide cover, and after surviving 1 minute, you would fall down a floor and the boss would switch to rapidly pulling and slowing. The boss maybe would have 2m health or so. Then, once killed, all of the players would 'levitate,' into the boss room. Finish this later, I'm about to fall asleep :/

 

couldn't you take some inspiration from Runescape bosses? They're both rpgs.
koff koff Telos koff koff.
Y'know, if it is possible, you should create stages of a boss. like detect when the boss is at a certain amount of health, then change mechanics and stuff.