i think that the Oryx boss fight was the best boss fight in the game because it wasn't "how much damage can you do before the boss enrages" but instead "How well can you complete the mechanics of the fight" He was also the most threatening looking boss in the game. The problem with the whole raid is just how long it would take to beat it on hard mode. Most parts were near impossible for an average team to beat with 5 or less people so unless you had a 6 man team of self-res warlocks, 1 person dying would cause a wipe and sometimes people would just leave making you have to waste more time finding another person on LFG.