I like this

There were some ideas came to me last time when I saw diablos (is that diablos?) from void ark. Since in the old dungeon we met many doors, in a raid there might be more? Then every time we start the raid it will randomly open 3 doors, each for one full party to go in, all have different encounters inside. Maybe when A kills right mobs it can give B a buff otherwise a debuff, or maybe B needs to play cards with npc and win x times to help C find it's way in darkness, if any party stuck and can't move on, all people have to suiside to restart...

I told a friend this and he said, you are going to kill the whole dungeon development team as well as players lol

But seriously, a few random or flexible content in a dungeon will make the game much more fun. ：)