I don't know if it's really fair to call Nami's protagonists "too perfect". I don't think characters have to be nasty or selfish to be realistic - not everyone is like that.
I understand that conflict is what causes drama in stories and makes the stories interesting, and having flaws in charcters can help create conflict. However, a character can still be flawed without being selfish or nasty. For example, quite a bit of conflict is caused in 'Starry Flowers' by Periwinkle being confused by new feelings and experiences that he doesn't know how to deal with - his inexperience, and his inability to recognise his feelings and face up to them, are flaws in his character. And this depth is given to him without needing to give him negative qualities. Plus, as another example, we have Pastille unsure of what to do because of how others perceive him. This depth and conflict to his character, and his story, comes about from outside forces, and not from making him nastier or stupider or anything like that - because Nami doesn't need to do that!
I personally like to read about charcters who are decent, good people, but who nevertheless have interesting lives, and get into interesting conflicts and have to find ways to overcome them. I think a character can have depth and be a decent person at the same time.