OP, talk to me about cities, because I disagree with your vision here. I don't want any hub city, optional or not. I don't want any side quests and I don't want many NPCs. If I see no one but enemies in the entire game, I wouldn't complain. So, talk to me about what you are thinking here...
Sure. Basically, what I'm talking about is a place Samus can explore that is populated with others. The best was I can describe it is the pub in star wars where luke meets Han for the first time. It does have to be as big or complex as a city in GTA or something. Maybe Samus visits the city because there's reason to believe that there is a nest of Metroid larvae, and the entire city is at risk. Whatever, I just think that Samus is much closer to Boba Fett than people give her credit for, and a city of fugatives giving her bounties to hunt would be a cool way to explore that side of her.