The premise of a dueling academy makes a lot of sense when you consider the fact that Yu-Gi-Oh! is about a children's card game. While the importance of a children's card game seems exaggerated in the viewers' eyes, you have to remember that in this animeverse, it -isn't-. Duel Monsters is the most popular--and clearly the most influential--sport of the world. Plus, when you realize the Academia still has the required graduation classes (though you won't see them too much on-screen), you realize that the school is a typical high school--just one with a very specialized "Ivy Leage" program.
Still, while the premise doesn't have flaws, the way it was carried out does. The first half of season one made GX seem like a slice-of-life anime, which wouldn't be so much of a problem if the plot was at least consistent rather than having these separated one-shots. Then when GX actually started having substantial plots, it seemed like another series taking itself too seriously. A white hole in space sending proxies to bring about destruction? A deranged hermaphrodite demon seeking her lover? A force of darkness wishing to unify all existence in nothingness? Sorry NAS, not buying it. What probably made these plots worse was that they were arranged in a "What enemy will I face this school year?" fashion.
The art was average. It didn't thrill me, but it didn't disgust me either. No more to say on that. Now as for music, that was actually GX's best asset. The OPs and EDs weren't the best, but the OST soundtracks were. They did their job of accenting the situations quite smoothly. If an upbeat song came on, the situation was happy or comical. If a slow and sad song came on, the situation was depressing or dark. And if that one song that raised your spirits came on, you knew the protagonist of the duel was making his comeback.
NAS dropped the ball with its characters. Too many characters introduced at a time with too little development reserved for each one. Judai, the main character, was a Gary Stu that didn't get a background story until season three. The background wasn't even good either, turning out to be a contrived DM reincarnation rip-off with pathetically shallow "I need to grow up" development in season four that made him nothing more than an ass. And the other protagonists only got their little development in season one, and were shafted in season three with the appearance of the Academia champions.
Still, I found myself enjoying the series while watching it. Much of the bashing GX gets is in hindsight, when the fans start looking back and realize the flaws they overlooked when they first watched it. In the end, the GX anime turned out to be run by a group of people who had no idea what direction they wanted to take the show in; they would rather insert any random and unnecessary bit of occult history and symbolism if it made viewers think they were actually putting any thought into the series. (And let me tell you, GX is riddled with occult stuff if you know how and where to find it.)
I suggest that rather than watching this anime you read Kazuki Takahashi and Naoyuki Kageyama's manga adaptation.
