User blog comment:FairyRaven/Fairy Tail Chapter 362: Natsu vs. Jackal, Review and Commentary/@comment-119.95.232.64-20131129112258

Maybe people just hyped the 9 Demon Gates. If I remember right, Grimoire Heart was the strongest dark guild pre-timeskip. By extension, it would mean that Tartaros was weaker than Grimoire. And as seen in the Grand Magic Games, the 7 years that passed didn't give noticeable power ups to the other characters.