I remember once reading in one of his previews that he didn't want instant fame or anything, but rather a readership that will in twenty years' time just as steadily go to the bookshop to buy a new Sanderson book. He's achieved exactly that with me. In twenty years time I will certainly be among those happy ageing fans trotting to their local bookshop to buy the latest Sanderson.
I trust him implicitly to write a good book. I don't have any reservations as to what the book is going to be about - a familiar universe or a brand-new one, magic or politics, heroes or heroines. He's good at what he does, and that doesn't seem to waver. I loved the awesome Mistborn trilogy, I loved the fluffier Elantris (of course, in Sanderson's meaning of the word, which spells it like "beautifully touching amidst suffering, politicking, magicking, character-building and brain-twisting"), I was happy with Warbreaker, and now I've finally read the first book in the Stormlight Archive, The Way of Kings.
I honestly can't believe I've committed myself to reading an epic fantasy series (10 books are announced) while 9 are still waiting to be written. It probably means I'll be a whole different person by the time the finale is released, doesn't it? I know I've publicly announced my love to thick books and volumes many times, but it's always been balanced by my unwillingness to read something too epic and wordy, aspiring to recreate whole universes, and even more so - to something yet unreleased. I suck at waiting, and I get annoyed with it and its cause easily.
Why did I do it, then? Because it's Sanderson, and I trust him.
His worldbuilding is awesome. Even his stand-alone novels could boast new, genuine and fascinating magic, religion and politics behind it, as limited as they were to a single book. Given more space to play around, a bigger chessboard with more pieces, he really gets it going. It's never simple, never straightforward, yet it's always clear and it's a living, breathing world.
His plots are great, because just when you think you have some answers he twists the meaning of everything and you realize you've been asking the wrong questions the entire time. He gives you clues, he sets the stones that you think are going to be a steady house, and builds a castle instead. Or an underground city.
His characters are likeable, even the protagonists. How many books today can offer me more than a coupla intriguing underdogs and creeps to like and feel invested to? Sanderson has these strong, humane and essentially good characters that make the journey throughout the book a pleasant, rewarding experience. They have their flaws, obviously, and more than their share of trials and choices and whatever he has in store for them, but you're hardly ever going to lose respect you feel for them.
Ultimately I think his books are of the kind that make you a better person, even if by a tiny degree.