I have watched both the versions of A Love so Beautiful, the difference between the korean and the chinese version is that the korean version has 24 episodes each being 20 minutes long, where as the chinese versions has 24 episodes with each being 40 mins long and yes this did affect the plot-line a lot as the developed and growth of characters presented in the chinese version were not at all seen in the korean one.

Korean format focused more on the school years of the characters.
The Chinese original version was, on the other hand, more melodramatic and mature, with a larger focus on family problems and the characters’ adult life which helps one grow on the characters and know about them more deeply.
The Korean version is not a step by step adaption of the original, it just takes some plotlines and creates their own story which resulted in the lack of dept and the plot being left shallow. The drama has a very fast pace, and, at times, it’s too fast and makes things feel rushed.
Unfortunately, this remake failed to deliver the sweet cute chemistry and heart that the original C version did.
I liked the C version and was excited for the remake.
I think they really miscast this, there was zero chemistry between the leads and the female lead's acting just looked really cringe and didn't even suit her.
The male lead was just stoic and i didn't feel any connection or likeness towards him to be very honest, the C version had a stoic male lead too but we actually got to see his character growth and how he let down his walla and changed for the sake of his girl.
Now coming to the other characters, the second male lead visually i would say yes, but he left me disappointed as the C version one was really charming, i felt bad for him throughout the drama as i could see how much the girl meant for him. The K version had a nice male lead, yes he did a lot for our female lead as well..its just he didn't leave any mark for me.
The drama is an epitome of bad casting and direction.