I am not familiar with this particular anime, nor any of the others you mentioned.
But getting to the question of redoing a second season always brings to my mind Gunslinger Girl. Season 1 ended with the apparent death of one of the girls (I forget her name), while the others are enjoying each other's company watching fireworks. It was the perfect downer of an ending clearly marking that the girls are doomed -- even if it did vary from the manga.
In season 2, the girl is revived! After that, I am told the series matches the anime totally -- and it totally goes downhill. I would have preferred it to stay darker, rather than semi-dark. How about instead of a fight to the death, Triela and Pinocchio develop an attraction to each other? They break their conditioning and try to run away together. But hunted by both sides, they realize they are just delaying their fate. Rather than surrender when cornered, they take each other's lives dying in each other's arms. It would have been much more effective than the cliche ending from the manga.
Changing the art style didn't help much either.
Bookmarks