Making a System of Magic

Most fantasy worlds have some kind of magic. The Southlands, the land of 

1. An author's ability to solve conflict with magic is directly proportionate to how well the reader understands said magic.
2. The limitations of a magic system are more interesting than its powers. What the magic 
3. Expand on what you have already before adding something new.

These rules are all well and good, for a certain kind of storytelling. However, I must take issue with them.

First, I don't think a system such as this is appropriate for all stories. It really depends upon the 

What about the other readers? What happened to magic that feels ... well, 

The second problem I have with the codification of rules is that we already 

In my opinion, there simply isn't any need to invent another set of rules which are functionally identical to the setup-payoff exchange. It's redundant. Restated as rules of dramatic tension, Sanderson's laws of magic would look like this:

1. To do a dramatic reveal and solve conflicts with X, first set up possibility X.
2. To preserve dramatic tension in the rest of your novel, set up the things that can't be solved with X.
3. Don't set up new things if you don't need them.

Rules 1 and 3 are essentially restatement of Chekhov's Gun. Rule 2 is a reminder that introducing unfamiliar elements to the reader requires a little bit of work to establish dramatic tension. Taken together, they're no different than the rules of standard drama.

Don't get me wrong: I don't think Sanderson's rules are 

I want a system of magic that can begin as a wondrous mystery, but then which can evolve into a known quantity, and then into an existential threat once its secrets are known. You can't get that if you're tied to the idea that everything must be understood by the reader throughout.