First time poster here, really enjoy Kdramas although I'm quite stuck at the moment. My favourite genre by far is action although not mindless action. It has to be mature and not cheesy if you know what I mean.
I'm looking at something along the lines of Bridal Mask which was epic although it tailed off a wee bit at the end and Chuno Slave Hunters. I love period pieces too as long as they have bad ass action and preferably revenge based.
Those 2 were epic, I tried iljimae but found it way too cheesy and thus gave up on it.
Empress Ki. I just finished it, and EPIC is the big word that comes to mind for me. It's a really great series. Also, if you're looking for some good action, I really enjoyed Healer.
Uh, coincidentally the same male lead. He's gawgeous.