@RyukMasaomi I can explain for BLEACH, but I hope that the reasons transfer over to Naruto, keep in mind i only know of trace facts about the Naruto series:
BLEACH jumped the shark too damn much and shouldve ended when Aizen was defeated;
what i mean by "jumping the shark" are the iconic scenes in most fighting animes, most commonly when the hero finally is face-to-face with his rival/main badguy and its brawling time. the moment where all the hero's training and determination pays off, and her FINALLY gets to test how great he is against a challenging opponent.
sorry, got in the moment
anywho, Tite Kubo's main crime is that BLEACH got too many seasons and too many arcs. personally, the story would be as perfect as it gets with the Intro, "save Rukia Arc" then Aizen being all "bwahaha ima da badguy," Ichigo getting stronger via Vizard training, raid Huecho Mundo, kill an antagonist and END STORY
No ripoff Aizen w/ fire clam
No ripoff Aizen making a Zannpakto rebellion
NO CLONE ARC
and dear YHWH, the Fullbringers; that really puts a ravaging Electric Scallop in my undies
why did the main badguy HAVE to look like Aizen?
why were the Fullbringers the ONLY outlet for Ichigo to regain his powers for the 3rd time?
and poor, sweet Chad; they demoted him from "bad-ass Mexican with Hollow powers imbuded with the Vim of his Grandfather" to "actually these fullbringers taught me how to harness my power"
Kennpachi better slaughter those damn Quincies; Wack-A-Mole Style.
you want to pop out of a 1200 year hole just because you got a little spanking? well then allow us to wop you back under the rock you were hiding!