Yeah all I meant by saying that BioChroma was more complex was that it was more complex to me. I understand the whole "What comes up must come down" (steel and iron, obviously. Although that saying doesn't quite apply, but you know what I mean) really well because, well, it's kinda apart of life. Plus, think about it a little. Tin increases your senses, pewter increases your body's abilites, brass and Zinc roit and soothe your emotions, Copper and broze reveal and hide sources of other allomancy. Just doesn't seem hard to grasp to me. Biology kicks my butt however which is probably a reason why I think BioChroma is complex. I completely disregarded Aeon Dor by mistake though, and now remember how flipping hard it was for me to grasp. I'll give you that one lol, but in all seriousness, Allomancy WAS easy to understand. BioChroma takes a bit more, esspecially when considering the sheer possibilites of it (plus it's complications with actual use and mastery of commands) which was showcased somewhat at the end of the book by Susebron getting a tongue.
I didn't mean to start an off topic discussion lol. Just stating my opinion and all.