User blog comment:FairyRaven/Fairy Tail Chapter 329: Seven Dragons, Review and Commentary/@comment-4829046-20130430111358/@comment-60.53.103.218-20130430131733

Dragon Slayer Magic is stronger than the average magic in terms of destructive powers but its not all that omnipotent either. For Natsu's situation, i guess its more to the fact that he isn't actually serious.