User blog comment:Joekido/Chapter 490: Oda's big suprise/@comment-3075024-20131230181855

I am not really sure which mangaka was it who started the whole idea of "time-skip" which results in NEW character design, power-ups and gives time to create new conflicts in the world that the protagonists will have to face in the coming arc. To my memory it was Naruto that did it first but I might be wrong, and maybe after seeing how well it worked-out .. Oda might have also wanted to do something similar cause he realized that with the current strength of SHs, he might have to make New World little less-chaotic for them to concur.. so in-order for him to go WILD with this imagination in New World, he needs to make SHs STRONGER .. in very short-time. Thus, time-skip which happened that Jeo explained and why.