Haters gonna hate. It's not about trend. It's been beating all other mangas in sales every since it started in 1998.
When somethings tops the ratings and sales for 14 years, that means it's good.
You're just being a little kid, judging stuff by their cover. Read it/Watch it before you judge it.
People that don't judge things by their cover rate the mangas.
Anyway, what purpose does insulting One Piece serve? Less people will watch it cause you think it's a bad series? It makes you feel better?
Yes, pull out a list of best selling artist of all times. (Not just for 2012 or 2011, cause that just proves it was a trend or is a trend, pull out the sales and ratings for artists of all times).
On topic: Whats good about Fairy Tail is that it takes much from One Piece, the best series out there. It uses a lot of the same elements and style One Piece uses, which is the recipe for success. It becomes pretty repetitive, and really have a really straight storyline(I mean like no end goal, or even if there is an end goal, the main character isn't pursuing it), so its very static series, where as Naruto and One Piece are very dynamic, if you know what I mean.