Psikerlord#
Explorer
My problem with the death saves thing is if you, as DM, want to make the fight lethal, you have to deliberately gank a PC. And that's just not going to make anyone at the table happy. Sure, it's realistic and believable that that critter takes the time to dump a couple of attacks into a downed PC, but, it feels very antagonistic as the DM. If I killed a PC because of a failed save or a good die roll, I felt that I was a bit removed from the PC death.
In 5e though, it's going to be pretty obvious when the DM is trying to kill a PC. I think it's one of those things that the table should discuss - make it clear from the outset that baddies will usually/always try to eat a downed PC before play even starts. Particularly if you want to be consistent about it. Either do it all the time, or none of the time. Otherwise, it's going to lead to hard feelings.
It's not even realistic though to attack a downed PC. Not when there are viable threats up on their feet. Even healers on their feet. You would simply try and disable the healer first.