If I have any gripe with Sanderson's writing, it's that his magic systems are just a little too elaborate for my taste. Maybe it's a generational thing, and younger readers who grew up learning elaborate rules for playing computer role playing games expect a magical system to be thought out with all this detail that I have a harder time getting into. I enjoy it when a magic system has some internal rules and logic, especially when those rules help with the world building and advance the plot, for example as in Jordan's Wheel of Time books in which the "tainted" nature of the male half of the magical "true source" has affected the entire culture and history of his world. I would agree that those kinds of details can be useful in creating a world which seems real. (I've read Lord of the Rings many times in my life, and I still have no idea what kind of magic Gandalf is actually able to do).
Many of Sanderson's rules of "Allomancy" (a magical system in which some people are born with the ability to gain special powers by ingesting certain metals) accomplish helpful plot purposes, and make sense in ways that can be kind of fun and symbolic (the Newtonian idea that every magical act you perform has a consequence and reaction, for example). But Sanderson's magic system soon becomes so elaborate that it can stop seeming like magic at all, and instead feels like either the science of an alternate universe, or the overly developed rules for playing a tediously complicated video game. Nevertheless, that's just my own personal preference, coming from someone who learned to love reading Fantasy in an earlier era. And it ultimately didn't keep me from still loving these books.
