First and foremost I would say that I did watch "Itazura na Kiss" and I didn't like it. Unfortunately, I didn't know that this show was an adaptation because I definitely wouldn't have watched this.
This is my opinion so you are not obligated to agree with me.

Xiao Xi- as a high school student being weepy, clingy and immature makes sense but even as adult there is no growth. She cries all the time and doesn't learn from her mistakes. She is a complete submissive. In the end it seemed like she has a little strength but that bubble was busted really quickly when she saw a little bit of tears in his eyes. "Did you forget all of the tears you shed for him on the second leads shoulder?"

Jiang Chen- I do not understand if its bad acting skills or the character is a robot. His expression never changes whether expressing love, anger, despair or happiness. He dominant and manipulative. He thinks very highly of himself and treats everyone -especially the woman he loves- as trash. Basically, I haven't found a single quality that I like about him. In college they were in a relationship but it felt more like only she was in a relationship. At the end when they get back together, he is totally taking advantage. He is the only one benefiting from that relationship and she is the only one comprising in the relationship. He doesn't care about her at all especially not about her happiness. When you love someone their tears hurt you more than it hurts them.

There is almost no character development in any of the main characters. I wouldn't want to promote this culture (the main male leads attitude) for the next generation.