No matter what the conditions or variables that affect drama ratings, Link was never going to get high ratings unless they had maybe PSJ and PSH as leads. The plot was never going to capture the general audience but YJG has no ratings power without a strong or popular female/male lead to carry him. MGY has almost no presence in South Korea, her last drama was carried by HIY and CEW to overseas popularity and domestically CEW is adored by the general public for his looks and personality. He just got his 3rd drama offer in less than 2 months. Poong works because sageuk never fails in South Korea (unless you are YSH who manages to turn everything he touches into a flop) plus the story is easy to get into and short at just 12 episodes. KMJ is also a more compelling actor than YJG even though they look alike. He also manages to have great chemistry with his co-leads something that YJG fails at miserably.