Here's an idea: Your everyday typical loser lead from a harem anime ends up an exchange student in America after a typical misunderstanding where the lead falls face first onto a girl's big bust, who then gets her revenge by tricking him to be an exchange student. He ends up in a typical 50s-80s style nuclear All-American family, the long suffering dad, the doting neutral housekeeping mom, the liberal anti-establishment son that hates his dad, the materialistic gold digging daughter, and the kid that says the darndest things, but somehow he fits right in, the Japanese harem lead becomes the ideal son as his nice guy traits become utilized to the point where he evolves from a loser to proactive character with a backbone and the only character that suffers is the dad due to his own kids causing him pain. He also does most of the chores, learns to drive a car, exercise, putting on some muscle gaining self-esteem, kinda showing that taking him out of the harem formula was probably for the better, think of it like Shimon from Gurren Lagann transforming into Kamina. Oh and a typical anime villain(shonen type, think Dragonball, Naruto, Bleach etc) follows him all the way to finish him, but he never counted that he became competent, and after a few typical anime mishaps, said villain loses and ends up becoming the slave to the youngest child and his cynical evil neighbor friend ala Grim Adventures of Billy and Mandy. In a nutshell, it's basically harem lead minus the harem, fanservice, mishaps and misunderstandings instead he gets to be in a family:
Plus a bit Grim Adventures of Billy and Mandy with the anime villain getting tortured by the youngest brats, the teenage daughter, and their neighbors that are expies of Steve Urkel, Beavis and Butthead, George from Seinfeld and Lazlow from the GTA games:
