One very big positive point at this drama is that it's not about love or anything cliché. There's just this bully type of guy who has to do some extra activity so he can pass. Nothing extraordinary here but he decides to get into the boys rhythmic gymnastic club (the reason being at first a girl) and he meets people who, eventually, have a huge impact on his life (which are just three). He changes, slowly but surely, and he becomes this trustworthy and beautiful person. There are a lot of situations they have to go through like a member of the group being homosexual or the personal life each wants to keep hidden. What I'm trying to say is that the subject is friendship. Where's friendship, there's trust, there's help, there's happiness and it will always exist, no matter what, because that's what true friends are for. A friend in need is a friend indeed, after all.
Anyway, Koji's role is the leader of the boys rhythmic gymnastic club and he lives his dream because of Azuma. They go through rough times and they are made fun of but each character has his own story, his own issues and it captivates you from the start. The tumbling world is quite difficult and each time I watch these actors do those moves I am amazed.
I don't think this drama has bad points, at least from my perception over the subject. I do believe it moves fast but if they would have made it longer I guess viewers would've gotten bored. That's actually a bad point at Hana Kimi and OHSHC, where there was enough material to prolong the series at least three more episodes.