Joker wasn't that well-developed since he was the same character in every appearance. But he's not supposed to be a developed character as much as he is simply an archetype/plot device.
Character development doesn't only mean character change. It means the process by which the story establishes and explores the character's personality. The character is being "developed" in the sense that the writers are building up and elaborating upon the fictional construct that is the character. Sometimes that's done by showing the character going through changes, but sometimes it's done by gradually establishing or revealing things that, in-universe, have been part of that character's nature all along. Think of it like developing a photograph (film, not digital). You're not changing the content of the photograph, you're going through a process of revealing what's already there.
In other words, development is an act of creation or revelation on the part of the storyteller. Paul Dini
developed the character of the Joker superbly, because he added clarity and nuance to the character and gave us a very strong sense of how the Joker thought and acted.
My other favourite thing about it is the episode "Meltdown". I really hate what the episode of "The New Batman Adventures" called "Cold Comfort" did to the character of Mr. Freeze, but I think "Meltdown" redeemed the character, giving him a MUCH more satisfying send-off from the Timmverse. He became someone the audience could connect with again and we got a moving conclusion to his arc.
Ironic, then, that both "Cold Comfort" and "Meltdown" were written by the same person, the late Hilary J. Bader (though she shared credit with Alan Burnett on the latter).
I never saw future Metropolis. I would love to see a series like this with old man Supes with the beard and Lois long gone, would be interesting. A grittier, more jaded Superman who has to rediscover his beliefs.
Didn't you see "The Call"? We did meet
the older Superman, along with the future Justice League, and he bore a resemblance to the
Kingdom Come version of the character.
To me, Shriek was symptomatic of what was wrong with BB rogues. Here's this acoustic engineer who's developed a sonic weapon and is trying to sell it to Powers. Okay, makes sense. But Powers tells him to use it to kill Batman and suddenly he's an assassin in a fancy costume.
Part of that is wrong. Shriek was used to demolish the historic district of Gotham. Part of which, Bruce wants to keep going due to his parents dying there. Powers wants Shriek to kill Bruce then to eliminate the threat and then Batman get involves.
Yes, okay, Powers wants to demolish the historic district and kill Bruce, but why the hell hire an acoustical engineer to do it? Why not use professional muscle?
This is...wrong. You can't look at TaS as simply a vacuum within a medium. What TaS did was draw from years of other materials to create their universe. Beyond had to come up with basically scratch material. It ended way to quickly to really do anything or flesh out their characters.
On the contrary. The creators of the DCAU weren't just drawing on what came before with B:TAS and S:TAS. They created entirely new, worthwhile characters such as Harley Quinn and Livewire. They completely reinvented characters like Mr. Freeze and Toyman and made them far richer and more engaging than they'd ever been in the comics. They proved over and over that they were capable of creating rich, original characters and improving on what the comics had created. But these same people, when doing BB, failed to live up to their own past achievements.
I agree as well that some of the villains like Spellbinder are a bit bland. but I but them slack because basically they didn't get a lot of episodes in.
Paul Dini only needed one episode to make Mr. Freeze one of the most compelling, tragic, unforgettable villains in the entire history of the
Batman franchise. In B:TAS, and largely in S:TAS, they had the good sense to
start by establishing a character strongly right off the bat, to lay a solid foundation for subsequent appearances. In BB, for whatever reason, characterization of the villains became an afterthought. Perhaps because they were so overworked, having to make three shows at once.