I could name a bunch of incredible drummers who had an amazing influence on metal music and still do to this day, but honestly if you have trouble getting into Pantera then you might be better off staying with hard rock. I could understand James Sullivan being very impressive if you haven't heard drummers like Gene Hoglan or Krimh... hell, even Chris Adler. He's certainly good but there are a lot of more complex and more creative players than he was, who are often unaccessible unless you're willing to take a little more bite and aggressiveness in your music.