I wouldnt mind respawns in a game like this.. Maybe you kill some Orcs in an area once and then after some time passes ( X in game days ) maybe something else comes along like Goblins or Trolls that decide to make that place home. Respawns dont have to be about mindless killing but more about making the world feel alive instead of killing off a group of critters and that ends up making them extinct in that region.