So I recently finished Falling for Innocence and I absolutely adored it. I'm actually really sad that I finished it so fast. My favourite part about it, though, was the changes Min Ho's personality goes through throughout the drama. It was my first time seeing such a dramatic change in a character and it was really fun to watch as he basically turned into a completely different person. I was wondering if anyone knows of any dramas that have something similar? It could be caused by anything from basic character growth to amnesia or cellular memory like with Falling for Innocence, I'm open to anything. I think I now have a sweet spot for character development like that. Thanks in advance to anyone who can give me some recommendations!

I was going to recommend Kill Me Heal Me but I see you've already seen that ;;

Last Cinderella- the male lead's attitude totally changes
The Lover- certain characters seem to 'discover' themselves so change in that way
Six Flying Dragons- they change characters clearly and believably from almost sheep-like followers to bloodthirsty leaders.
Misaeng/ Incomplete Life- you see the main character develop his confidence
Night Flight- a movie not a drama but you see one of the leads go from a rough gang member to vulnerable and lost.
Oh my Ghost (it's on you PTW list) by the end of the story the girl is no longer a doormat.
Legend of Concubine Zhen Huan - several ppl including mc change due to them living as concubines
Angry Mom, 3 of the side characters go through massive changes
Arang and the Magistrate
Beethoven Virus
Empress Ki
Faith
High School King of Savvy (2nd Lead has a good change)
Iljimae
Love Rain
Mary Stayed Out All Night - Almost everyone changes in this)
Moon Lovers
Night Watchman's Journal
Personal Taste
Sassy Go Go
The Royal Gambler/Jackpot
Warrior Baek Dong Soo
You're All Surrounded
 Autumn's Concerto ---> the male lead
 Doctors ---> female lead
Dragon Zakura ---> the high school children in that class
49 Days ---> some of the main characters
Limit
Nobuta Wo Produce

I can't believe no one has mentioned Bridal Mask yet! Joo Won's character goes through so much in that drama! 
Decoded
Heart to Heart
Beautiful Mind
Mars (Taiwanese version)
Iljimae