As much as I hated Nago in the beginning, I got over it when he started getting his ass kicked more and became a bit of a joke. He never stops being self-centered to a point, but he does become entertaining after losing IXA to Kengo.
Narutaki is ridiculous from the start of the story to the end. Barely a character at all.
As I'm watching Boukenger right now, I find that I wish Natsuki would just disappear. Her personality gets old after a while.
Sailor Luna... Nuff said.