This encapsulates why I am always wary of getting into Sanderson. He's been recommended to me by my best friend and I often see him recommended in general. The one that gets recommended the most- Stormlight Archive- seems like a huge time commitment.
People always talk about his worldbuilding and magic systems, but I don't care about any of that.
I care about compelling, complex, and layered characters with depth and nuance. I care about social commentary and critique, either via positive example or negative example (i.e. "here's how things could be if things were better in this aspect or that aspect" or "here's how things are and how it negatively affects people"). I care about deep themes and profound insights. I care about well-written dialogue. These are the elements that make a good story, to me.
Asking generally (this is directed at his fans ITT, not in a hostile way, just in a curious way), does his work have any of that? Because I never hear people talk about any of those things with regards to his work.
Generally speaking more to the topic, even if his worldbuilding and magic systems are good, I don't see how that's going to really capture the minds of a general audience that won't care about either of those things, especially the latter. I feel as though if his work does not have at least one of the elements above it's not going to be successful in the way that GoT or Lord of the Rings are successful. Worldbuilding I think can only get you so far.
But then again, a lot of things in the MCU (dialogue, character depth, etc.) are merely serviceable, so perhaps it could hit big and be like the MCU of the fantasy genre.
I wouldn't say his work possesses all of that. I would put character depth and dialogue quality at that level of something like an MCU/blockbuster movie. They typically have a bit more depth than that if only because the characters can be explored so much more in these huge books, but you don't read a Sanderson novel if you want tons of depth and complex morally grey characters and deep exploration of societal themes. Stormlight has his most complex characters and themes, so if you wanted to try his work, I would recommend that one. I love his fantasy books, personally. They're legitimately great, but not for literary snobs.