Jordan provides an entertaining read, most of the time. His world is detailed and thickly populated. He has interesting ideas. The villains are properly creepy; the heroes are properly heroic. So if your metric is the "summer read" metric, then Jordan is just fine as an author.

But Jordan's writing is lacking in several areas. There's no thematic content to speak of; Rand's temptation in later books is about as allegorical as WoT gets. There's no real message contained within the series--nothing that makes you actually examine something of significance, nothing that makes you sit back and think (besides convoluted theories about what will happen next; I'm not talking about suspense). And the prose itself is nothing special.

Contrast this with Gene Wolfe's BOOK OF THE NEW SUN series, an incredible work that forces to reader to wonder what the self means, what memory means, and how we confront ourselves and our memories. In his words,

"By the use of the language of sorrow I had for the time being obliterated my sorrow - so powerful is the charm of words, which for us reduces to manageable entities all the passions that would otherwise madden and destroy us."

and

"It is said that it is the peculiar quality of time to conserve fact, and that it does so by rendering our past falsehoods true."

I doubt you could find equally meaningful sentences in the entire corpus of Jordan, to be frank. And I just snatched those out of the Quote of the Moment.

And that is only talking about science fiction and fantasy. There is a vast world of literature out there, a world populated by figures like Keats, Shakespeare, Dostoevsky, Eco, Vergil, Chaucer, Faulkner, Hemingway, Steinbeck, Nabokov, Camus, Kafka... the list is endless. It's not even a fair comparison in these cases, of course; these are the true greats of writing.

But it does mean that Jordan, as authors go, is not a particularly good author.