I'm curious as to how many people would watch a season 2. I personally feel like the show wrapped up fine and while I may watch it, should it ever come out (highly doubt it), I would rather not have a S2.
I know many are feeling cheated of a happily ever after, but given the genre and the constant cliffhangers at the end of every episode, this ending is more consistent and less your normal c-drama cliche ending. Therefore, the open-ending isn't much of a surprise and actually seems much more fitting IMO.
Plus, you can imagine the ending how you want. ? Unless the novel that comes out after gives us an epilogue of some sort.