One of my biggest complaints with Fallout: New Vegas is that, despite being a courier and technically being apart of this whole delivery group, you don’t actually get to do a lot of mailmain-ing? I feel like the idea exploring an extensive fictional world through the lens of someone who’s just transporting packages is an untapped well of potential. Sunless Sea could get that vibe sometimes, but most of the time in that game I feel very distanced from the world and the story (+ plus the roguelike elements lead to you repeating stuff a lot).
In general, I think the idea of just being a small part of a wider fantastical world is under explored in all of media, not just video games. Maybe I don’t wanna play as the chosen one? Maybe I just wanna be the dude who makes sure the chosen one get’s their mail?