The Pokemon Anime, currently in it's Diamond and Pearl season, has been running ever since Pokemon Red and Blue were released. While it is one of the longest running cartoon shows, period, and the longest running show based on a game, quite frankly, the show has degenerated over time as nintendo and the pokemon company redefined and made clear what goals they had for the show as well as what audience it was designed for.
One of the things that I noticed back in the beginning of the anime was that there seemed to be an unusual degree of cooperation between those that were in charge of the anime and those in charge of the games. In the first episode alone, we were introduced to a bird pokemon which would be known several years later as Ho-Oh. In addition to this, when Ash challenges the Viridian City Gym to obtain his eighth badge we are treated to a vision of MewTwo destroying Giovanni's installation. That is, I believe, the only correlation between the movies and the anime. Which is unfortunate, since creating a connection between the two and expanding on it seems to be an excellent way to generate a true plot line. As of right now, the diamond and pearl anime has degenerated into a predictable plot. The individual episodes all run off of a standard script, with only minor deviations, and the seasons seem to have become set in rhyme with those that came before.
While 4Kids has never been known for doing even half-way decent dubs, it seems like the decision to replace the english dub with an entirely new cast of voice actors, was a mistake. Even though the original voice actors weren't great, the fact that those voice actors had dominated many seasons and had established the characters made it difficult to take the transition. Speaking for myself, that was pretty much when I stopped watching the anime on a regular basis. I still keep up with the movies, desperately hoping to see some geniune plot development. The movies have always been pretty good, and they started off very well. MewTwo Strikes Back was excellent. MewTwo was an excellent character in his own right and a major obstacle to the heroes. In an anime where there seems to be little question about whether evil is anything more than a foot note, MewTwo was a welcome distraction. Throw in the good guys demonstrating some rudimentary intelligence and basic knowledge of tactics, and it was honestly pretty solid.
For those of you who haven't yet mosied on over to the manga downloads section of the site, I strongly recommend downloading some of the Pokemon Adventures manga. It is 'excellent'. I would seriously consider putting it on par with Bleach and Naruto. Regardless of problems you may have with Kubo or Kishimoto, there is no denying the popularity of those two mangas. Pokemon Adventures is though everything the anime is not. It has a real plot line, time actually passes and characters age and mature, and it fits seamlessly in with the regions and different moods established in each set of pokemon games. I've been reading the manga for years now, and even have been able to acquire some from Singapore, the only place left which prints them in English; they've continued in Japan through diamond and pearl, though those haven't yet been translated into english, from my understanding.
Currently, the only improvements I've observed, since the Pokemon company took over direct control of the anime, is that the characters seem to exhibit a slightly greater knowledge of battling tactics, and even that is sadly behind what the games have demonstrated.
Wasn't Ash supposed to go back and get Pidgeot? Guess not.