I liked the idea that: "The reason the literal devil is acting like a silly comedy act, is because his daughter has the inborn power to alter the personalities of living things around her" -- but it hits a hard wall by going around actual subjects that can easily destroy the kid's innocence. Giving Dou the ability to infect people with kindness is brilliant, but it wasn't enough. The mere mention of meat, war and extortion won't be able to fit in her world view, for an instance, but we seen none of that. Heck, the fact that the gruesome, tyrannical demon-lord is doing nothing but babysit his daughter, is also a problem that wasn't glossed at. His empire is built on violence, and that violence is running short for months now, yet nothing happens. Overall, the one thing that really bugged me in this series, is that she's just an innocent kid who wants to have things her own way.
In the chapter in which she takes down a bad guy, the focus immediately shifts towards "She saved people", instead of: "She used violence against someone else." By focusing on her selfishness, they'll be able to break down her character and prove to her that she cannot save and help everyone. Some people and things will be always outside of her perfect, pink-tinted world. By saving one person, she throws the other away. She cannot have win-win scenarios forever.
That being said, we all know that this manga is just here to be cute and that's about it. It's just too bad that it didn't stay consistent long enough, by giving more explanations as to how come they cannot corrupt her, or why it is that she is so difficult to corrupt to begin with.