User blog comment:FairyRaven/Fairy Tail Chapter 423: Do It All for Love, Review and Commentary/@comment-194.103.203.254-20150309125626/@comment-5268982-20150309165056

It's entirely different from the beginning of One Piece after the timeskip:
 * Natsu went off to train all by himself(and Happy) to train for almost a year. Luffy spent 2 years under one of the strongest people of the world. And still, he was only able to easily beat Pacifistas which were the same level as he was pre-timeskip. Which means, they did not have the ability to train to put up a better fight, unlike Bluenote.
 * And for those who say that Bluenote may not have been training at all those entire 8 years: From his introduction, Bluenote was as power hungry as it gets, and someone to whom strength is the most important quality, not unlike Jiemma in that regard. After losing once, and also joining another guild and becoming that guild's new ace, I can't fathom him staying as he is and not wanting to grow stronger to get back at Gildarts.
 * Had a third point but forgot.

Anyhow, bottom line is that they were 2 entirely different circumstances, as explained in the first bullet point.