User blog comment:Sargenttacos115/Why are Sting and Rouge so weak?/@comment-24016459-20131110061912/@comment-4829046-20131110074243

Yep. Training is essential. What Natsu basically did everyday when he was free was either laze around in Lucy's flat or go on missions that basically have him do the same thing. Blow everything up. Sure he sparred a lot but it wasn't a spar that would increase his overall skill as a First Gen Dragon Slayer. Even with second origin he only got "power" not "training" or "experience". The times he used ingenious improvisations of his magic were onetime only. Hopefully he will use them all again when he masters Dragon Force.