I think he's a bit of a pretentious cock who keeps spitting out the same tropes, often not original ones but one just far enough of the mainstream for it not to get noticed.
Plus he's often set up alongside Alan Moore and keeping in mind I'm not a screaming comic fanboy and even though The Wizard or Northampton is inconsistant, awkward, lazy and has his own particular obsessions he still has more talent in his weirdly long little finger nail than Mr Gaiman shall ever posess.