Prepare for a rant people! We've seen it happen to anime, and now it is infecting manga also... Beware!
Here are two examples:
> "Blade of the Immortal" is a really good manga. And it could have been great if only it stopped sooner instead of going into that political-historical retoric that just slowed down the action and the enthusiasm of fans.
The introduction of a bazillion characters mid-story was the first red flag, cuz I had no idea where they were coming from and what they were gonna do with them... And sure enough, neither did the author. Best solution, kill them all only at the end. A very shakespearean way of dealing with it: Don't know what to do? Kill everybody.
I give a super plus, in art, in the composition, in the theatrical, the historical setting, the beautiful portraits of death with flowers, birds, patterns... it's almost like poetry in motion coming out of each page. There is nothing, nor there ever was, something like it. But I think extending the manga was a huge mistake. If it ended in number 13 (I believe this was the author's original idea) it would have been a masterpiece. Instead, ultimatelly, it was a glorified piece of Japan's history open for marketing and sales.
> "Naruto" has got to be the worst written manga I ever read.
Don't get me wrong. I like the universe, there are some cool characters, and the special powers are impressive. It's almost like a Marvel X-Men kind of thing. Unfortunatelly, that is all.
The plot is, or was, rather simple. But with every new character, every new chapter the story got re-wrote, re-twisted, and re-told. Every new character played the old ones for a fool, and every tangle just left a knot in the reader stomach.
The basic story had only three (that's right three) arcs: Orochimaru, Akatsuki, Madara. That's it. But the way they stretch the storyline was ridiculous. First, not one of the important characters seems to die (with the exception of Neiji). Naruto has appears in only two ages (young and teen), but in teen he has like seven transformations. The great ninja war has a ridiculous amout of "last bosses", if this was a videogame I probably just stopped playing. Every boss just seems to want to have a good heart to heart and then he's suddently good (spends decades killing people, but one session with psycologist Dr. Naruto and all is well). Spare me the emotibable to make everyone watery-eyes (I got my girlfriend for that) and just use violence!
Furthermore, most fights have more tears than punchs and kicks. Sure there's a lot of firepower thrown around, but there's actually very little contact. And a freakin God at the end? Were the hell did this come from? Like I said, with every new character, everything changed. And everything was 'sort' of explained (not really do) thru flashback - God there was a lot of flashbacks. The only good thing I got, the best thing I might had, was the fight between Madara and Gai! Now THAT was a fight! Gai going all "Asura's Wrath" in the end was beautiful.
When Naruto started has a little boy everyone expected the next Dragonball. He would visit each village, fighting enemies to get the 'Bujii', collect them all while making friends with others that carry the same 'curse' as him. In the end they probably tried to release them to the Mana Tree only to realize they were tricked by some companion (Sasuke probably). And then they would fight him, then maybe a stronger version of him, and then they would win!... That's it.
But NO! Instead they tried to stuff the cheese pizza with even more cheese and everyone got annoyed, bored, and sick of it. To the point they just had to end it... Thankfully!