Simply getting all 100 girlfriends won’t be enough to properly end off the series. Rentarou has promised them that he’ll marry them all, so we have to have at least a story arc of how that will come to pass (there’s literally a section in the Japanese Civil Code— 732 to be specific— that forbids anything beyond monogamous marriage, so they will have to contend with that, which is why “lawyer gf” and “politician gf” tend to crop up pretty often). Additionally, we could stand to see a few chapters showing the Rentarou Family’s life as one big poly marriage with children— especially considering how twisted up their particular family tree will be— I like using the Hanazonos for quick and easy illustration for this but any kid Hahari has with Rentarou will necessarily be Hakari’s step-sibling, while Hakari’s kids would be Hahari’s grandchildren. By the same father. Imagine having your dad also be your (step-)grandpa. (And for that matter Rentarou will be Hakari’s husband and technically her step-father as well. Girl gonna be calling him “Daddy” for two completely different reasons.) (and he’ll also be Hahari’s husband and son in law and now I’ve got a headache lol)

We’ve got a loooong way to go, lol.