Nerfed Death (3.5e Variant Rule)

Nerfed Death
Being killed through a single roll is no fun for anyone. So here's a nerf to instant death that doesn't remove the functional aspect of instant death.

The Change
Any instant death effect (typically a [Death] spell but can include other spells which instantly kill but don't have the [Death] tag) instead brings you to -1 and dying. Any fast healing or regeneration is temporarly suppressed until you are brought back to positive hp.

Any instant kill spell done on a dying creature kills them as normal for the spell or effect.

Effects which don't kill (such as petrification) operate as normal.

The Side Effects
Diehard becomes a much better feat.

Monsters are still effectively dead with this method, but PC survivability goes up. You can also use instant death traps more liberally since, as long as someone survives, they can recover the party before they die.