most of that content is so easy now, because everyone has highest lv/stats for the content, so most of the time you can skip mechanics
Like Diablos fight, when it was new, you had to do memory game with the doors, and avoid his AOE, now you can just burn him down before he casts it. the only thing you need to think about, is to stun his sleep.
but i might not remember the full fights on top of my head, but as soon as i see a mechanic, i'm like, right, i remember, and react,