Dramas where the lead changes for the better

Autums Concerto

Back to 1989

Im not a Robot

Shining Inheritance

Innocent Man

The Secret Life of my Secretary

The ML mistreats the FL because of a misunderstanding, but change after all misunderstandings are cleared:

Secret

Kleun Cheewit

One of the best, and cutest stories I've ever seen about a ML who becomes a better man for the FL is Dr. Gang (2006) about a gangster who's on the run for the police, goes undercover in a hospital as a doctor, there he falls in love with a female physician.

1. Dream high - lead female changes for the better

1. Orange Marmalade 
 Main male lead stops needlessly hating vamps just for being vamps.
2. Memories of Alhambra
Main male lead had a bigger temper and lesser regard for the welfare of others at the beginning.

Hotelier

When one of the main leads falls in love with the manager of the hotel that he wanted to buy and then  resell, after many many episodes full of hate, pain, stubbornness and thoughts of a businessman, he decides to put aside his plan (he had been entrusted with that work by a partner and for him his work was the only priority) - - - [The character is much deeper than this, so I encourage you a lot to see the drama if you can. The internal processes of this character are very deep and well developed]