A Grande Doutora (2012)

So, I recommend Shin Don only because it has common historic characters with Faith. You'd watch it if you have educational purposes (want to learn more about the period).

Both are historical dramas with political intrigue, romance and magic.

Both are time traveling dramas. :DDDD

Both dramas have same concept : Time travel, historical. On them both characters will live a sweet love story

In both dramas, the couple is balanced, they love and sacrifice unconditionally
There is no love triangle, nor nagging female
Male lead falls first in love
Between country and love, both ML will put first their love
Both have happy ending

"A modern-day surgeon is kidnapped and taken back 700 years to the Goryeo Dynasty in Korean history."

Time-traveling and doctors that change the fate of the past.

They are both set in the Joseon era
They are both dramas worth watching.. if you liked one then you should definitely have a go at watching the other.

Although Vigilantes in Masks is not supernatural/ time travel inclined the filming style, animation included, and the seemingly laid back attitude of the male character reminds me of Faith's.

Both are fantasy dramas and faith has Lee Min Ho :) You get to see time travel and it is a good story.

All the gods will be leaving before the last rain of doomsday. However, an ordinary human girl unexpectedly puts a dent in their plans to retreat thus causing the world to move towards the unknown. Based on the animistic mythology of the Amis tribe, the gods are no longer willing to bless the land that is plagued with environmental issues. One by one, the gods depart the world they once loved. A human girl discovers that the opportunity to reverse her destiny lies within herself and her guardian. Before the final day of judgment, a love story between human and god unfolds.

Both female leads are doctors with similar personality types. They both get transported to another realm/time period. While Faith is more of a medical drama and sageuk, W is more of a modern day romantic comedy.

If you take away the supernatural time-traveling theme with the main girl, it revolves around King Gongmin, Princess Nagook and General Choi Young who seem to play a bit role in the background of the Six Flying Dragons. It's definitely a good drama to watch either before or at the same time as Six Flying Dragons to get a good background picture as to why Goryeo is looking the way it does in Six Flying Dragons.

Both dramas have fake looking special effects, time travel, and characters which look like they are doing a cosplay play. Although, Faith's are slightly better than the Holy Pearl's.

My Country is heavy on the action and bromance and less on the politics, which I think Faith can be comparable to that plus their approach to this genre is so unique. The number of episodes in Faith may be a bit draggy, but overall it's really a solid drama.