I watch Naruto and have seen all the episodes, in order. The basic plot is interesting enough to keep me watching, but I know I speak for thousands when I say the filler is ridiculously stretched and prolonged. Although they do this for real, legitimate reasons (mainly manga related), it can piss people off and really does keep one's enthusiasm limited when you know that an entire episode is going to be about opening a door, or introducing a character, or starting a fight (and lets not forget the 30 minute speech before the actual fight). Also remember than it takes about 4 or 5 episodes, on average, for a fight to be done and over with. When you do the math you realize it's possible for an entire season (24 episodes typically) to go by with as little as 4 major fights taking place, and about 5-10 minor battles. This creates a divide in the fan base. Fans expecting/wanting more fights are going to be disappointed that there are none, and fans who are more about the plot/characters/story are going to be disappointed because filler is slowing the plot down.
Despite the fact that there have been entire seasons worth of filler, I continue to watch Naruto in the hopes that it gets back on track, even if only long enough to fulfill a quarter of the overall plot of the series before it has switches back to filler.
For me, Naruto's saving grace, as an anime show, are the memorable characters and the plot. If it didn't have these things as strongly as it does, it wouldn't balance out the fact that the filler is ridiculously prolonged. Normally I don't mind filler, as long as it contributes to the plot or characters' development in some way (Sakura, for example, is now more mature, stronger, and we're now able to acknowledge her as a very capable ninja who isn't a weakling or good for nothing anymore whining about her lost crush. We can now respect and like her even more because she's come a long way). Shows like Kenshin, however, have been outright cancelled because the filler lasted too long. Because Naruto is a bigger hit, it is not likely to suffer the same fate, but I think relying only on that isn't the answer, as any show is ultimately about whether the audience is satisfied. As popular as Naruto is, the fan base is indeed divided, leaving the show's ultimate fate up in the air.
