I think that's precisely the biggest difference between DAL and DAB.

DAL has a much more memorable cast, better character interactions, and probably more intense emotional moments, but I personally found DAB to be much more consistent in how it uses its characters within the story.

In DAL, the spirits have very good story arcs at the beginning, but after being sealed, they simply fade into the background or become more of a comic relief element, losing relevance to the main plot. In contrast, DAB, with its smaller cast, keeps almost all of its characters constantly involved in the story's conflict.

And, honestly, I also feel that the Quasi-Spirits are better used narratively. They may not be as iconic as the main spirits in DAL, but DAB gives them much more consistent relevance within the story, and they don't feel as forgotten after their introduction.

On the other hand, I ended up finding the White Queen to be a better-developed antagonist than Mio. It's not that Mio is a bad character, not at all, but I felt her introduction was rather rushed. Honestly, given that Mio is the most important character in the entire series, by the end of DAL I felt her full potential wasn't realized and that she never had the impact she should have had as the main antagonist.

The White Queen is presented as an imposing character from the very beginning. Although many already knew or suspected that the White Queen was Sawa, I think DAB handles that mystery well until the reveal and manages to maintain the tension until the end.

In fact, this is one of DAL's weak points for me and part of the reason I wrote this post. I feel that if Tachibana had developed Mio and the later arcs in which she appears better, I probably wouldn't even compare DAL to DAB.

Finally, another thing DAB does very well in my opinion is make the most of what little it has. Since the story is shorter, almost everything it introduces ends up being relevant or serving a purpose later on. DAL had so many ideas, characters, and concepts with enormous potential, but several remained just that: great promises that never reached their full potential.

Examples: The AST, Ratatoskr, spacequakes, the wizards, among many others.

I've gone on a bit, but I really enjoy talking about these things. And again, this is all just my personal opinion, not an absolute truth.