If you played EverQuest years ago, you know about one shots. If you started playing MMORGPs recently, you'll find a lot more cases where even the toughest mobs do not have a kill maneuver and the ones that do are scripted to where you can determine how to avoid or prepare for it. The main difference between the old school way and the new school way is that back then you only had personal experience to teach you and even then RNG was big. You never quite exactly knew when you were about to get squashed - which made it thrilling.

Games like ARR are watered down 90% outside of boss fights and thus we become accustomed to it.
I don't mind the increased difficulty(even though it's not) that instant death provides, but it has to be used sparingly. Being one shot, after spending an hour beating down redundant trash mobs, is demoralizing and makes you not want to play. Being one shot by a boss that you fight straight away and can try again without any penalty or time delay, is acceptable.