When it comes to fantasy, “accessibility” is a watchword. So often, good ideas are buried so far beneath dry prose and leaden world building that they are scarcely given a chance to surface.
It’s not so much a problem of an impatient reader as it is the impenetrable density that some authors thrive on.
Brandon Sanderson does not believe in making the reader wrestle with his prose until the story gets interesting or until the bitter, bitter end; instead, he presents something readily palatable and understandable. I will admit that my knowledge of the fantasy canon remains minuscule, but I would suggest that Mistborn: The Final Empire, the first in a trilogy, is a good book for beginners and veterans alike.