I felt the same. But only for the first 200 pages of book 1. Once they get to Shadar Logoth I enjoyed the heck out of it. Book 2 I powerread in 1 day, same with 3, 4, 5, 6, 7,
8 was a bit of a step down and his slow pacing was in full effect, but he fixed that in book 9. book 9 ended with the biggest cliffhanger in the series. Ever.
10............Book 10 is one of the worst books ever written and you can actually skip it. More happened in the first 50 pages of book 11 than all of book 10 combined. When I say skip it, I literally mean it. Every friend I have ever gotten to read the series said "Nah, I won't skip it, you must be exaggerating" only to finish the series and say "JESUS, you are right, you can literally skip that book and not miss a beat. You are literally left in the same place with no major plot movement at the start of book 11 after that cliffhanger in book 9"
Sanderson's books were a breath of fresh air to finish the series. Book 8 started to drag a bit with how Martin wanted to tell his story and it continued like that. Dragging.
Sanderson read the notes of what he wanted to accomplish and literally said "there is no way to finish this in one book." and did it in 3 books of nonstop action and plot resolution.
Book 14, the final book is amazing. nobody I know could put it down. It was the stamp of absolute satisfaction. I never believed the series could be resolved to my satisfaction and I was wrong.