I really enjoyed writer Kim Eun Sook dramas, i've seen three dramas written by her, City Hall, Goblin, and Secret Garden, but in order of my favorite, first would be Secret Garden, gave it a 10, it was so funny and had a really enjoyable story and characters, I really like Hyan Bin's character in Secret Garden, the OST is one of the best in kdrama, it's one of my first dramas also. second would be City Hall, gave this one a 9.5, it was so good imo, really funny, and the story was always good, don't remember being draggy at all, and the OST was so good to, it really fit the drama, but i also really like the story and characters, Kim Sun Ah's character is one of my favorites, also Cha Seung Won's character likable to, despite it's 20 episodes and being a political drama, I never thought it would be one of my favorite dramas of all time, don't even remember why I started it, and third would be Goblin, gave it a 9 because the story was quite good, characters, and ost, though the drama was pretty slow and had some boring moments, I enjoyed it overall and found it quite refreshing but the reason i really like it alot because of Gong Yoo was in it.
If I have enjoyed Kim Eun Sook's dramas, then I might enjoy Descendants of the Sun, A Gentleman's Dignity, and The Heirs, but I cannot wait for Mr. Sunshine, it's going to be a hit, I find Lee Byung Hun a really good actor, he did a amazing job in I Saw The Devil, A Bittersweet Life, and Joint Security Area.