For me, I think alot of RPGM games just need more bodies within their maps, even if the characters don't say another that contributes to either the main plot or a super minor backstory. Some comments could be something as simple as commenting on the weather. One good example so far in the game imo is the guards, currently I've seen no plot relevance to any of the comments the guards make as you walk by them, but I'm still seeing what they have to say each time.
Often times the worlds feel empty from the lack of people just out on the street in the city/town. Unless this is some rural town, there should be lots of people out on the streets during the day in Japan. And then within FOG, there's maybe max 20 other characters who are "human players", it just makes it seem like a dead game.
The recent subway scene was a really good imo cuz the train was actually packed with people, as Japanese subways are. Alot of the people didn't actually do anything, but just the sheer number made the world seem more alive to me.
Clutter is a really good word for it, cuz it doesn't have to have a purpose other than just being there.
