I want to address that.

"Do you like it?" is not a way of determining if someone is a good writer. It's a way of determining if someone tells an interesting story. I like reading Dan Brown books but I don't think anyone would even try to say he's a good writer. He uses cheap cliffhanger devices to keep you turning the pages. His characters are as deep as a puddle of spilled water and his descriptions are awful, like they've been lifted from the most cliché Harlequin romance novel.

Dan Brown is, in short, something like a car crash. You know it's terrible but the story is fun and so you can't help but read. He's not a good writer, though.

Being a "good writer" typically means several things:

1. Style. A good author chooses his words well, doesn't waste the reader's time and avoids repetition of stock phrases.

2. Aesthetics. A good author has descriptions that paint beautiful pictures. This isn't limited to traditional description, either. DomA mentioned Flaubert; I would add someone like Nabokov. Consider the beginning of Lolita:

Lolita, light of my life, fire of my loins. My sin, my soul. Lo-lee-ta: the tip of the tongue taking a trip of three steps down the palate to tap, at three, on the teeth. Lo. Lee. Ta.

She was Lo, plain Lo, in the morning, standing four feet ten in one sock. She was Lola in slacks. She was Dolly at school. She was Dolores on the dotted line. But in my arms she was always Lolita.

3. Ideas. Books can be simply entertainment, but usually a good author will fuse entertainment with ideas - the "moral of the story" as the old saying goes. Part of being human is being mortal, knowing that we're going to die, and trying to make some sense out of life while we're here. When a book has a message, it resonates with people and they take that message and make it a part of their lives.

If we're going to look strictly at the genre of fantasy/sci-fi, then you can add "world building" as an element with many facets, where a good author will create a world that feels authentic by creating plausible histories, cultures, language fragments and a framework for why or how things like dragons or magic exist.

In the first three categories Jordan cannot be called a good writer. His style is very formulaic. The books are not written with aesthetics in mind. There are no big ideas.

On world-building, some people think Jordan came close. I see an uneven result, with a terrible "Old Tongue", a lot of countries that really sound the same and a history that is only partially plausible. However, given the absolutely atrocious efforts of others in this field, Jordan isn't so bad.

The story is fairly interesting and keeps people reading, but it's not the way it's told that people like. If someone else grabbed Jordan's story and told it in different words, people wouldn't be upset. To be specific, there are people who like Goodkind and/or Sanderson's continuation of the story at this very website.