The only major hole in this theory is the fact that Vin's earring seems to stop her from burning the mists. She doesn't have it when she fights TLR, but she is wearing it during MB2, when she cannot burn the mists. If the earring is hemalurgical, and burning mists is hemalurgical, why can she not do both at the same time?
Indeed. That is the question.
Clearly, I've missed something. My theory was always that the mist-burning was Allomantic in nature (see "The Mists" for more info).
Hemalurgy is inherently different from mist-burning on a fundamental level. It has to be, because one attracts mists and the other repels it.
In fact, my theory further said that Hemalurgy made it impossible for Vin to burn the mists. Because her Hemalurgical earring pushes the mists slightly away, even when she does not know it, that little bit of resistance makes it impossible for her to actually burn the mists. If you think of mist-burning as Allomantic (which it should, logically speaking. She is essentially just creating another Allomantic metal operating under the rules of Allomancy. None of our observations apply about Hemalurgy--such as a blood sacrifice or metal inside of you--explain or otherwise make sense of the mist-burning. Thus, it is Allomantic.) skill, and her Hemalurgy as a hindrance, it makes perfect sense.
For the majority for MB1, she wears the earring. Kelsier even says it should be okay to wear, so she wears it for the majority of the book.
In MB2, we definitely know of it being worn.
The only two times we explicitly know of that she isn't wearing it is 1. During the fight with the Lord Ruler, and 2. At the Well of Ascension.
Now, this tells me something... if she can't do it during MB2, while she is wearing the earring, then during the LR fight, she is
not wearing it, enabling her to use special Allomantic ability.
Problem solved.
