Best Male Leads 1st, 2nd, etc...

Drama: Flower Crew. 

Role: Lee Soo/ Kim Soo 

Here he is second ML, but far better than the first who is closer to the type of lead being avoided here. He is kind to the female lead, never insulting her or treating her as lesser. He is good to others as well, it is not just 'only care for the girl I want'. He is the best thing about the entire drama.

Drama: Nothing Gold Can Stay

Role: Wu Pin.

I saw this one more recently and Wu Pin probably surpasses all male leads. He is very supportive of the female lead, smart, diplomatic, and caring for others. 

Drama: Flourished Peony part one.

Role Jiang Chang Yang.

I am only basing this on the first half of the drama. After seeing so many possessive and rude male leads,  he was a breath of fresh air. He does not man handle the female lead and is more of a comedian.

Drama: Road to Splendor

Role: Zhao Ling

He starts more carefree and funny and changes as the drama goes, but that good part of him remains throughout adversity. No cruelty to the female lead and cares for others.

Drama: New Life Begins

Role: 6th Prince Yin Zheng

This drama altogether is unique. His role here may have been my first exposure to a good male lead.