Yeah, I've always kind of had a problem with Mai and Kita. Mai was supposed to have attitude and be a love interest for Tsurugi, but she always just seemed like the most stereotypical you could ever write a female in a superhero story. Fainting at everything, never really helping (she needs her dad to solve one of the show's bigger mysteries). She never seemed like a love interest, either, and Kita never seemed like he was supposed to a rival for her love. All three just got along.
As for Kita...I never really liked the character, but maybe that's just me being biased. Even as a kid, having seen Changeman first, I was like "Why isn't this guy as cool as he was as Change Griffin?" You know Kawai can be cool, and I feel like he's wasted in the show, they have him looking like such an idiot for so much of the show. I read Hiroshi Kawai/Kazuoki Takahashi was supposed to play Kenta/Black Mask that year, but he ended up as Kita, and...I think he would have been better off taking Maskman.