In my honest opinion I see the Goro Goro no Mi devil fruit as the most powerful in the One Piece universe. Here are 7 reasons I believe makes this fruit the most powerful (read until the end because this fruit has one massive flaw).
I would like to compare Lucci and Doflamingo fights with Luffy to determine which of the two was the best. Of course this is based on my own personal opinion, but feel free to debate in the comments.
There is Liam Neeson badassery, there are Chuck Norris facts, there is even the epicness of Gon transformation from Hunter x Hunter, and then there is Whitebeard from One Piece.
Even if Eiichiro Oda didn’t draw the G8 Filler Arc on the manga to me G8 is canon and here are 5 reasons why.