I don't know if I can articulate this properly, but I really like the 5:1 gender ratio. Like, it's still severely skewed, but it's not as extreme as other stories with, like, 1000:1 or something. Because of this imbalance in ratios, social norms and gender roles differ, yet there is still a sense of normalcy. I like how that normalcy sometimes makes you forget the social norms of this universe, which is how the MC ends up in the situations he does.
Also, this story seems to tackle interesting themes about such a society. Take Seira, for example; yes, she is a creepy stalker who deserves at least some kind of punishment, but her actions and behaviour are a product of a culture that pressures women into finding a husband (and with such a big gender ratio that's pretty difficult).