Not uncommon to first person single player RPGs. Your not supposed to grind, its not a MMO. It maybe boring but it also adds a bit of realism.
I know your not supposed to grind, but other non MMO games (I hate MMOs because of the grind) do it. Either by respawning some enemies leaving an element of danger still in areas, or NPCs starting to roam outside the city/village walls giving a sense of achievement as the area is now safer due to your actions, but all in all keeping the world a more living world. I have played many where nothing respawns but generally on those you rarely revisit areas.
So surely it would be more realistic if stuff did happen after you clear areas? For istance, why would it be unrealistic if say you clear a dungeon of demons and afterwards a small group of bandits seize the opportunity to set up camp there? Or would it be unrealistic if travelling traders start to populate the roads as they are now safer? Or even random encounters of champions having a skirnish with some form of pest/beast (there are few in this, but only 3 I've found).
Anyway just my thoughts.
