The End of Justice League
The funny thing is, the creative team were reluctant to do so. During Batman Beyond's run I asked Bruce Timm and Glen Murakami about a possible Justice League series. Timm wasn't keen on the idea, saying, "When you have a show like The Justice League, where you've got not just Batman and Batgirl and Robin, but you've got Superman, and Green Lantern, and the Flash, and all these people who have really extra super powers, and [you're trying] to come up with things for them to do every episode, and to come up with opponents that are strong enough for them to figure logically, it's kind of a hassle. That alone is enough to make me think I don't want to go there. Not only that, but by having that many main characters in a 22-minute show, it's hard to focus personality-wise on any one character. The beauty of a show like Batman is that you can really get into that one character, into his personality. I'm not saying it couldn't be done well. I just have no desire to do it."
As with Robin and Batman Beyond, they eventually found a way to solve these issues. When Justice League premiered on Cartoon Network (another corporate cousin to DC), most stories were two-parters, generally featuring only some members of the team. About the only time you saw the entire team at once was during the occasional three-parter.
But after the thrill wore off, it became apparent that, for the most part, the spark wasn't quite there. Overall, Justice League got slacker in the writing department, relying on fan goodwill and nostalgia—how could any long-time fan not feel a thrill at hearing "No man escapes the Manhunters?"—over tight storytelling. Whereas the previous series were perfectly enjoyable to people who weren't comics cognoscenti, Justice League sometimes required explaining. But the show looked good, felt good, and by the second season had a few episodes ranking among the best of the DC cartoons.
In the third season Justice League became Justice League Unlimited, and the creators again had hit their stride. There were no more multiple-episode stories and the cast had expanded to include just about every DC hero imaginable (with no Firestorm—where's the love?), but a continuing thread linked all the stories together, culminating in the phenomenal fourth season, which built not only on earlier Justice League episodes but on Superman, Batman Beyond, and even Static Shock. The final battle, and the coda of the season's last episode, made the previous wobbliness all worthwhile.