Guild Wars 2

why not make all npcs invulnerable and just sit back and do nothing.

they’re just annoying and contribute absolutely nothing anyway; they’re garbage

would fix a lot of dungeon progression script bugs

I guess the only problem with this is that it’d break immersion – in GW1 only a handful of NPCs did this, and those seemed to have some sort of excuse.
This would prevent teams from wiping, waypointing and running back to the boss before the NPC dies (avoiding a reset)…