KEEP!! Psychopath: Ji Chang Wook.

Dismiss. he looks like such an softie, I can't imagine him playing a psycho :P

Perfectionist male secretary (yeah kinda like male ver of kim miso from what's wrong with secretary Kim but with a lot more personality that her character obviously lacked...): Park Seo Joon

LOL. Keep! Let's reverse it. Park Seo Joon's sassy, arrogant and unbothered female boss in that one (but actually nice): Park Min Young.

KEEP!!! Kdrama writers really need to make this happen or else I'll riot 

Boxing champion: Seo Yeji

Keep. An experienced pilot captain: Ji Sung.

keep

Android/robot Jang Ki Yong

Dismiss. Jung So Min: badass female police officer.

Keep

Pianist: Lee dong wook 

(because his hands are absolutely gorgeous 

Sorry I couldn't find a better gif/pic T-T ) 

keep

Yang Yang: handsome aloof main lead

keep

A computer expert /genius hackerL

Keep

Professional Makeup artist: Park bo gum

Keep

boyfriend who can secretly read minds and wants to please you.     Hyun Bin 

Keep!!! 

ML with Psychokinesis/telekinesis: Im siwan