User blog comment:Lord Zeref Dragneel/Top 25 most powerful characters/@comment-25111584-20150812160455/@comment-3290324-20150813171407

Those stats came from the author of the series and are a good representation of how he ranked those characters. If Natsu/Gray/Gajeel were stronger, he would've given them higher stats. I'm not saying Natsu/Gray/Gajeel couldn't be stronger after the time skip, but the tiers for the main characters have remained pretty consistent and I personally don't see them changing anytime soon. :/