Tell me again why one shot kills are considered fun and rewarding?

I guess you did not read my post. Some one shot mechanics cannot be easily read or dodged. In one case, a white missile that is fired at point blank range. Even I was outside CQ range, it would have been impossible to dodge. Hitting the potion button is irrelevant unless you have the buff to heal even at full health as the damage needs to be applied first and by then I am not fast enough in the couple of ticks that takes my health away. If the screen is full of red effects it is difficult to see the echoes and their attacks.

One shot kills are to be expected but the player needs a chance to defend otherwise it’s just RNG whether you live or die and that, my friend, does not make an enjoyable session of playing.

When you aren’t familiar with the boss animations or their patterns, this is true. But you can learn those things and then you can dodge the mechanics if you have enough mobility. People routinely beat these bosses in hardcore.

40% DR is quite minimal to be honest.
besides, have to invest on agility, improve the movement speed, you can outrun the white projectiles.

You are going to love the new off screen one shot mechanic coming in 2.0. From two screens away no less!

LOL my movement speed is capped at 200%. But my regular human reflexes are just not that good to be able to notice and move out of the way. If I was a sorc or a range rogue maybe, but at CQ melee range, very hard to have time to notice let alone dodge unless I was bit by a radioactive spider and developed that spidey tingly senses.

It is what it is. To avoid the nuisance of dealing with these inane boss mechanics, I just abort and start again with a new run to get a hopefully different boss. Diablo’s a game and life’s too short and all that. Better to focus on the fun and leave those kind of things for the peeps who like that stuff.