Why feel the need to hype up one author by dumping, ever so slightly, on another?
It takes a **** ton of work just to get a series off the ground and then to have it run as long and be such a massive success as Naruto (and Naruto was/is bigger than YYH and HxH) is a once in a lifetime achivement for a small handful of people.
And if you want to equate number of series with success then Ken Akamatsu and Hiro Mashima have them both beaten (both have two or more finished series that are considered staples of anime and are currently producing more on a regular basis).
My point is, yes Kishimoto's Samurai 8 wasn't able to replicate the success of Naruto due to various issues with the storytelling (which is sad cause I thought it was fun). But that doesn't mean that Togashi is necessarily a better author. The manga industry is harsh at best, and WSJ have pretty insane demands of new series. Things just didn't line up for Kishimoto this time.