Sounds like you need to get a better eye for surroundings and other stuff. So far the casttimes and animations are long enough.
For the given fight, don´t know what´s gonna explained, but it´s seriously just staying on red or blue. What´s sometimes happen is that the boss swap the stonefaces, but that´s even a cast you can see.
For that knockback, it´s always 1 line. Otherwise you can stay in the correct line and use your antiknockback-skill. Stop doing DPS and just concentrate on mechanics to get used too. Pretty much everything in this game repeats dozens of times, so once you got used to something, you can clear everything beyond.
(You could even follow another person permanently. You probably won´t die then, but you don´t learn then too.)
I´ve never said that i want the complete game on my skill level, it´s just what ppl claim who don´t read properly.
I´ve stated more than one time that it´s not about difficulty only. It´s more about "not always the same". We got re-used stuff over and over again from each expansion, a beautiful but useless overworld and other stuff. Dungeons are just wall to wall pulls meanwhile the loot and adds have become completely irrelevant. Bosses can be solo´d and in stuff like savage the whole challenge is that 8 from 8 persons stay on the correct spot. And and and...
We just don´t get any new or challenging stuff. The game doesn´t even has a decent learning curve. A bunch of players are just getting carried through the content meanwhile the others are bored as hell. And instead of giving us a decent learning curve, SE gave us an "easier button" and many dumbdowns on classes.
I would be a fan of normal and hardcore dungeons, even with 5 difficulty tiers and special mechanics or so. But as i said, ppl has already been like "No, i don´t want to spend more than 10 minutes into a dungeon" or "No, i can´t complete it, it´s too hard, i can´t get the mount/pet there. So SE goes the lazy way and don´t put much efford into anything. Visually yes, but gameplay-wise not so much.
(This guy above seems to be my personal forum-stalker anyway. He´s writing the same sentence with other words on anything, so far just ignore it. He has seriously no clue.)