My first PC was an Elf and he should have died in the first adventure when some Green Slime landed on him. The GM was rather gracious and treated the slime attack more like a degenerative disease and allowed my PC to continue adventuring as the slime slowly overtook his body. In retrospect a good idea to not kill off a newb's character in the first session, but....
...well I've NEVER liked Green Slime and I've only used it a couple of times as a GM. Both times I telegraphed it's presence big time and the best I did, adversarial-speaking, was get a Magic-User to voluntarily have the Ranger lop off his (MU's) hand at the wrist. That was actually good times as a GM, but the player did that to his own PC....as that interaction was completely avoidable.
All of this is more of a related side-note to a larger issue I've always had with essentially instant-death. Now if a PC jumps off a big-assed cliff unprepared and plummets hundreds of feet to the ground....splat-city and no sweat off my ass. Suck it up and start rolling 3d6.
Right up there is the whole idea of Save vs. Death. Seriously? I've got an AD&D 20th level Magic User and his Save vs. Death is 10......so outside of having a Ring of Protection or some magical aids, he's got a 50/50 shot at surviving. Years of me playing this guy and some event comes down to a single die roll? Sure lots of crap comes down to a single die roll, but usually it's really more like a series of die rolls. A monster has to hit and has to roll high enough to do the PC in, but some random creature has an overpowered effect and your PC just happens to be nearby? Roll that d20 and hope it rolls high.....
OK, clearly something happened in last night's game.....
My group was fighting some plant-based monster and it had a spore attack that was Save vs. Death. Half of the party died, well would have if the GM didn't roll it back. Statistically it should have killed half the party and I don't think he expected that. Now I'll admit I didn't have a huge attachment to this PC, so death was no big deal, and even if I had said attachment......I know I should have taken my own advice and reached for the d6's.
Thing is it's not the PC loss that bugs me, it's the unexpected sudden and seemingly randomness that gets me. I just don't like that at all.
My thoughts on this aren't just to complain, otherwise this would be just a whiner post.
Harkening back to my earliest experiences, I think that the results of a Save vs. Death shouldn't be just straight up death. At a minimum I'd add in another die roll. If you fail the initial Save, do a 3d6 CON check. If you fail that, then kill off the PC. Otherwise, the PC's hit-point maximum is halved, and increases back to normal at the rate of level per day (i.e. a 6th level Fighter PC currently at 25hp, but has a maximum of 60hp, fails the Save vs. Death, but makes the CON check, his new maximum HP is now 30hp. He still only has 25hp and magical healing will only bring him to 30hp. The next day his maximum will be 36hp, the next day 42hp, etc.) The GM should describe the degradation to the PC appropriately and the nature of the injury should be such that magical aid (specifically healing spells) will not restore the damage, but it will bring the hit points back up to the current maximum.
My thought is that a Save vs. Death should be serious, but not detrimental to the point that a single die roll will doom the PC. The PC might luck out and make the Save, but if that is failed there is still a chance that the PC takes a serious blow that might very well lead to its death....., but if the PC is careful, the damage can be overcome.