Well, i'm not good of analyze either so here go:
Arata Kagami: I start with him first because he is the most easily to understand. Now come Arata Kagami. He share every trait of a Neo-Heisei main character and has the most clear character arc out of all Rider, but cannot be the main character cause it take him half series to become one.
At the start of the show he's got big dreams, but is insecure, clumsy, and generally feeling very uncomfortable with his position in life. He walks awkwardly. He flails when he runs. He sits like he never really belongs anywhere. He is assertive, but it feels like an act. While he is a member of a secret organization to protect humanity, he is just a part-timer.
Kagami felt inferior against Tendou and other Riders. He cannot henshin, had to tell Kabuto to kill the Worm mimic his brother cause he cannot do that,... . He's weak, and without the Zecter, he's a normal person in everyway. He doesn't has wacky trait like Tsurugi, Daisuke, Tendou, or the Hell Bros. He's just an everyman we saw everywhere, just happen to be in a war between human and Worm.
The series is a way for him to find his own voice, his own identity, who he wants to be, and finally became a warrior, a hero. Even as a normal human. Step by step, he leearn from Tendou, from other Riders,... And by the middle of the series, get a challenge, and become Gattack.
No longer is he passively following Tendou, he has his own agenda, his own beliefs and is more and more shown to be on the same level as the formerly unreachable and perfect Tendou. No longer is their relationship one-sided, they fight and save each other. No longer is Kagami sitting around looking up at Tendou, he is standing at his side,…