Far too many anime stories lack seriousness.
The biggest offender is the desire to write a story that can be continued indefinitely in serial publication. This leads to a subtle form of “status quo is God.”
The desire for a plot that never ends makes most writers wallow in pretty appearances while neglecting substance. When a writer is not willing to burn bridges, but he tries to build continuity, the result is pabulum.
Space Dandy is very enjoyable, but it is not telling an over-arching story. Dandy will never get any kind of character development, because his character is more important than the passage of time. Thus Dandy’s status quo is God. All the episodes that get made will just show us more and more of Dandy’s Eternal Now. Space Dandy’s plot burns bridges in one episode and completely ignores it later: there is no attempt at continuity. We can think of this as alternate universes containing alternate Dandies, or we can rationalize it otherwise.
However, Zankyou no Terror has plenty of character development. There are plenty of burned bridges. If anyone gets injured, they’re not going to heal quickly. If anyone dies, they are not going to come back as a zombie or a ghost or a replicant. (If anyone sees a ghost, it will probably be a dream or hallucination rather than a real ghost story.)
Cowboy Bebop walked a fine line between the silliness of Space Dandy and the seriousness of Zankyou no Terror. I used to think that Cowboy Bebop was perfect, and then I tried to give the first few episodes a serious viewing after a few years. It is not a perfect show. It may have created its own genre, but it was not the divine revelation that I used to think it was.
I think the creator, Shinichiro Watanabe, has said in interviews that he would be willing to change the plotline of Cowboy Bebop. Most viewers interpreted the ending of that show as definitive and final – I think the creator was ruminating on how he could somehow get another two seasons out of those characters. I suppose I’m glad that he has not done so.
I would like to see some other creator make a new show in the genre of Cowboy Bebop – that is to say, a show that bounces all over the map with competing sub-themes and a wild variation in musical atmosphere. Perhaps Space Dandy can be considered to be such a show, but Space Dandy is NEVER serious. A true successor would need to bounce all over the dramatic map, with some moments of silliness and many moments of seriousness.
So, for various reasons, I didn’t watch Zankyou no Terror or Tokyo Ghoul when they first aired and I’m catching up with binge watching now. Tokyo Ghoul is a competent re-imagining of shopworn vampire tropes that the West has done to death and back again. Nonetheless I enjoy it; it makes only very light demands on my emotions. Zankyou no Terror is a much more serious show – it is more emotionally draining than Psycho-PASS. The people in Psycho-PASS were in danger of death, mutilation, etc., but I wouldn’t feel very sad if any of them died; their world is a dystopia; death would be a pleasant release. The people in Zankyou no Terror have about as much to hope for as people in the real world. The absence of superpowers and magic and “lost technology” makes the conflicts much more emotionally draining.
Another factor is that just about all the major characters in Zankyou no Terror are trauma survivors of one kind of another. These people have suffered, badly, and they show the emotional scars in a way that the dystopian policemen of Psycho-PASS never did.