Custom Class: Mistborn

[Quiver]

Okay first off: this is not my creation.

It was actually proposed on another forum I frequent, a fansite for Brandon Sanderson's fantasy works. I told the guy who posted it that, while I've been playing Pathfinder for a little while now, I'm not well-versed enough in the meta to say how balanced or otherwise the class was...
... but then I thought you guys might be. So, with the designers permission, figured I would post the class here and see if'n ya'all could give any opinions on it.

It's in a google document so... link. (https://docs.google.com/document/d/16C_x3-rfL9_DngGw_9C1ep_7jeb13--vxT1jVfAetdE/edit)

Since it's a class based upon a work, I figure some background on the source material might be worthwhile:
Mistborn are characters from an epic fantasy novel series titled, uh, Mistborn. In the novels, mistborn are those who are able to access a magic system known as alomancy; they are able to consume metal (typically flakes suspended in vials of some liquid), and then use those metals to produce a magical effect, each metal having a different magical power associated with it.

[aimlessPolymath]

On mobile so I'll try to keep this short.
Metals vary widely in use.
Steel and Iron are OK ranged attacks, but locale dependent, tin is poor, and has awful duralumin uses, pewter is OK-ish but not great on this chassis, zinc and brass need better differentiation and clearer rules for use- most of the text is taken up by what looks like paraphrased quotes from the book; either bendalloy or cadmium (whichever makes you fast) is insanely good. Duralumin has a conflict between what it says it does (linearly enhance the power of burning) and the way each metal describes benefits individually.

The main thing the class needs is a natural progression of abilities. You get most metals at level 1- that's OK, but they barely improve past that. I'd suggest tweaking the mechanics for flaring to provide better progression- perhaps any given allomancer can burn up to their level in units of metal each round, and the net benefit of burning is given by that value. Duralumin would expend all of the supply in one round, but gives you up to 2 or 3x your level in benefits.
Example metal:

Tin
Capacity: 600 units.
Burning at least one unit of tin per round provides a +2 bonus to Perception checks. For every five units burned per round, this bonus increases by 1.
Burning at least three units in a round gives the allomancer scent and low-light vision; if at least seven units are burned, the range of scent is doubled and it improves to superior low-light vision.
Burning at least five units in a round grants the allomancer uncanny dodge.
Burning at least ten units in a round grants the allomancer 20ft. blindsense. Every additional two points burned extends this radius by 5 ft. If at least 15 units are burned, this improves to blindsight.

Note: A low-level allomancer can gain small, level-appropriate sensory bonuses, scaling up to longer-range sensing. On the other hand, a level 10 allomancer can leave it on a slow burn for a while, providing uncanny Dodge for up to 12 minutes, or burn it all in one go, getting 45 or 70 ft blindsight for a round, providing a quick snapshot of the nearby area (note that blindsight penetrates walls).

Do note that the protagonists in the novels benefited from Plot Power, and could easily be significantly higher than 1st level- if you liked, you could make this a PrC if you want to give benefits more appropriate for higher level characters(i.e. whatsherface from the first trilogy is a Rogue 4/Mistborn 5, and so can burn up to 9 units per round).

Class also needs prices per unit of metal, bad.