Why don't modern rpgs add something to mimic PKs in mmos?
One of the best things about oldschool MMOs was the possibility of getting killed almost anywhere, any time, by or more PKs. And not only getting PKed but also losing your gear or whatever gold you had on you. Then noting down the guys name or guild and then taking revenge on them at a later time when you powered up.
This made exploring dungeons or even collecting materials really exciting, because you never knew what threat awaited you. Always had to be on your toes, had to prepare, know escape routes, look for signs of PK activity (player corpses in weird places, etc).
In traditional RPGs there is never a threat or excitement when exploring the world, because trash mobs are around your level, their AI script is elementary, and you know when you are approaching a boss or actual threat, so basically you never get ambushed or experience getting chased down by elite npcs trying to kill you.
So why don't they add a sort of "getting ambushed by powerful foes" mechanic? Even running away is exciting if done properly.