RangerWickett said:
Make it harder to die.
0 to -9, you're disabled.
-10 to the negative of your normal hp total, you're dying.
Once you are more negative than your normal positive, you die.
Save or die spells don't kill you. They drop you to -10.
Yeah, I've already made it harder to die. But I've got to be honest: I've never considered a system as generous as yours! My system works as follows:
-1 to -9 hp means that the character is unconscious and dying (unless stabilized by traditional means).
-10 to -(10 + CON bonus + character level) means that the character has suffered a "mortal wound". The game mechanics of this are that the character cannot be stabilized without magical healing and will continue to lose one point per round until hp are greater than -10.
After that, you're dead.
This system has definitely helped with the character deaths a little. But in our last session, a guy with 3 hp was hit with a 34 point fireball and was insta-dead. That left everyone at the table with a bad taste in their mouths (including me). So I might consider trying a system like the one you suggest, or maybe the negative level suggestion.
Here's a system I've been thinking about toying with. (IIRC, it is similar to the rule in 2nd edition.) What if Raise Dead and Resurrection didn't cost characters a level, but instead cost them a point of CON (that can only be restored with Wish or similar magic)? That would have more of the flavor of the kind of necromantic magic you read about in fantasy fiction (i.e., the return to life costing the person a piece of their health/soul). It would also place a more realistic limit on the number of times a character can be brought back. Of course, in the long run, it would just cause more death because the character would have fewer hit points. So maybe it wouldn't work. But, like I said, it's an idea...
Thanks for the suggestions, everyone.
P.S. Merric, in response to your question, I also have 6 PCs. But (so far) I have not found that at lower levels they are able to keep up with the uber-bad guys. Maybe it's because my group is not as experienced or as finely tuned as yours. (Just guessing.)