Anyone who's talked with me for any real length of time will know that I think that both Naruto and Bleach started out pretty strongly, but then underwent a serious downwards turn. I think it's interesting to note that both of them went bad for exactly the opposite reasons.
Naruto's problems can be divided into two parts: the first is that the pacing's gone to shit. Things move arduously slowly. Almost nothing happens in a chapter. The second is that the supporting cast may as well not exist any more. Outside of Jiraiya's Incredibly Boring Adventures, can you think of any time in the past fifty chapters that anyone who is not an Uchiha has done something significant? Bonus points if they aren't in Team Seven.
Bleach's problems are pretty much the exact opposite of those. The pacing has also gone to shit, but it's not because nothing is happening: Plenty is happening, and each chapter is productive. The actual pacing problem isn't on a chapter-by-chapter basis like it is with Naruto. It's an issue with the plotting: too much extraneous shit is happening. There's fight after fight with painfully unimportant people. I don't have a problem with lots of fighting, but when the people they're fighting don't matter, it doesn't do anything but bog down the story and bore the readers. And for clarity, I'm not talking 'get the fuck out of my way, weaklings' fights, I'm talking multi-chapter 'victory at the point of death' fights. You know, like what the significant fights are. When even the most minor and inconsequential of villains is able to kick Ichigo's ass all over the place, how is he ever supposed to defeat the main villains? It just gets tedious after a while.
And the other issue is also with minor characters, namely that they're getting way too much attention. It seems like he's trying to give every single Shinigami he came up with for the Soul Society arc a place int he spotlight, and the main cast of humans suffers for it. I mean, don't get me wrong, Kenpachi and Ikkaku and Renji and Hitsugaya and all them are great, but there was a huge stretch in there where the human characters who are not Ichigo pretty much didn't exist. And then when they did get to shine, while rollin' into Hueco Mundo, the arc was dull and they all quickly got their asses handed to them. Poor Chad got punked again, despite getting an awesome powerup. This is the Worf Effect in action, people.
So...it's sort of interesting to think about. They have the exact same problems, in opposite directions. That said, I think Bleach has the better chance of recovery, because Naruto's decline has been accompanied by a sharp degradation of art quality, and Kishimoto hasn't made a story decision in ages that hasn't rendered me bald from sheer rage. I just get the sense that the dude just doesn't care anymore. Kubo, on the other hand, seems to be at least trying: The flashback arc has been pretty interesting thus far, and is actually moving places.
That said, if the chapter numbers are counting down accurately, and it's seriously going to be two years before we get back to the present, I might shank him. Let's exercise a LITTLE restraint, eh?