I must say, you are right about the chiness loli.>There was no overuse of plot twists à la Code Geass.
I don't really see what you are talking about, elaborate. Some others exemples?
And I still don't see what was "dark" about this. Yes both Nina and Hughes died but that was tragic, not really dark. Also there is a lot of VERY annoying part of the anime (episode with Mahjal (the old guy alchemist and the flower girl), the lame death of Scar. The annoying Wrath (I wanted to puke when I've heard "vrat" in french). Which make it less better than his anime counterpart. Perhaps when you were speaking about "code geass plot twist", you were thinking about the fact that sometime a character come and help them. (Yoki in the mine). But I think you are wrong giving the spotlight to thoses minor characters are what make me like it. Yes, you are right about one thing if we think about the "dark part": The rape of Rose.
Also, Dante and Rose always made me want to fap furiously.