There were some murmurlings a while ago on save or die mechanics, and whether it should be included in 5e.
Personally, I love SoD. A couple weeks ago in the game I DM, a Specialist (LOTFP Rules) decided he was going to open a chest. It was trapped. The player, who normally is very conscious of these things, forgot to say he was searching for traps first.
BWAHAHAHA!! says me the evil DM.
Of course, it was trapped. I had him make a save v. poison, and told him in advance it was death if he failed. True to LOTFP rules, there is no resurrection, short of artifact level shit. He's been playing that character for like 20 sessions and had a lot invested in him.
The look on his face, and on the whole rest of the group's faces, was priceless. I swear he nearly shit his pants as he shook the dice for the roll.
All eyes were on the die roll.
Faces were eager with anticipation.
The die was tossed across the table.
As it came to rest the whole group, players and DM were looking at it in eager anticipation!
I won't tell you if he made it or not. Why not? Why do you want to know? That "why" is the reason why we need save or die! Because it's the thrill of not knowing if you'll live or die that makes the game worth playing!
That's why save or die should be in the game. No other mechanic reminds you of the sheer randomness of life and death. No other mechanic comes closer to replicating the "shit happens" aspect of our lives.