I love jazz myself. I don't see why it should be singled out for criticism when every other art form, even the best ones, have suffered the same decline over time. Even so, a site that calls itself "Theory Corner" shouldn't avoid controversy. Here's an abridgement of the article by Justin Moyer called "All That Jazz Isn't All That Great." See what you think.
BTW, I stumbled on this jazz article from a mention on Mike Barrier's site. I went there to see if his new book is out. Apparently it's been out for a couple of weeks now, and it's on Kindle, too.