I think all the criticisms is a little harsh. Clearly there is a fanbase for the novels.
And JMS' writing isn't always the best. Babylon 5, season 5, was quite the stinker -- and there were plenty of other stinker episodes too. And don't forget the B5 movies; some were good and some were pretty bad.
And lets not forget that JMS completely stopped writing the comic book, Rising Stars after issue 21, essentially leaving everyone hanging and completely killing the book. I don't care what the circumstances were, that is just not a good thing to do to the fans.
So while I adore Babylon 5 and his run on the Amazing Spider-man, I don't find JMS to be the holy grail of creativity that others do. Nor do I side with JMS on the argument blindly.
(And don't get me started on Kevin Smith, another hack).
~Le