Really? You see in DtB there wasn't a single happy ending in any arcs and perhaps not even in the ending. Problems are solved but always at a great cost. Currently it's the same with the second season.
We don't even know if Hei has romantical feelings for Yin...heck even he doesn't know it. And we even less know if she's going to survive. Most probably not as everyone Hei wanted to kill died in the end even if he changed his opinion.
