I think Brandon Sanderdon is among the worst mainstream fantasy writers. He did make some good contributions to magic systems, but his prose is trash and filled with cliches. I once saw one of his videos speaking about writing “fight and sex scenes” in fantasy and you could in one second tell he had no actual real life experience in either.

So. It kinda depends. He is among the fantasy writer breed that kinda grabbed D&D culture and repurposed it into literature (or, maybe, “literature”). I think fantasy has so much more to offer literally than Sanderson and his plot-driven stories filled with 2 dimensional characters and worn-out tropes.

If you want to learn how to write in general, then, no. Sanderson is an awful writer. If you want to learn the ropes of the most generic, D&D campaign inspired, and hardcore magical fantasy, then well. Maybe so, but also not his style or prose. Sanderson represents a predominant niche in fantasty, but by no means is he a golden mean. Just like Joe Abercrombie represents GrimDark or George RR Martin political/historical fantasy. It kinda depends on the subgenre you want to develop yourself in.

But subjectively and personally: no. I think Sanderson embodies the reason why people who don’t read the genre roll eyes at it.