I kinda like the idea of removing routine from fights. Take the same good 8 people into Titan Hardmode. They will beat it the same way everytime unless someone screws up. The fight will be the same. You could set a clock by the rotations used in the group.

But remove the routine of the fight by randomizing the abilities of the boss and the fight becomes a new one each time you run it. Maybe set a cooldown so there's not 4x+ mountain busters for example, or maybe even let it ride and see how groups react to it. Allow players to use out of box thinking with their abilities for once. Obviously many fights would need rebalancing such as the example with titan during a heart phase... excessive back to back plumes would make getting the heart down in time a little heinous. Perhaps a failed heart phase makes subsequent mountain busters AOE for about a minute or so. Making the fight extremely crazy but still not unbeatable.