Save or Die not as a "generic spell effect", but as a plot device seems okay with me. If there was a fair warning about it (probably not: "Oh, and behind the next door, there will probably be a Medusa Paragon that turns you to stone, no save, forever", but "The Labyrinth of Stones is commanded by the first Medusa of the world. A Demon Cult is trying to free her from her prison to destroy this world once and for all. Stop them *several adventures later* Just as you enter the room, the Demon Cultist Leader is beginning to unlock the last locks of the First Meduas prison. Stop him now, or prepared to literally end up as a monument of failure." (That's obviously the "Epic Approach" to Save or Die - exaggerated to emphasize the story)