I imagine that the DTV movies have been somewhat like a prison lately. No one is really being allowed to create anything; they've just been turned into Xerox machines with pre-made graphic novels on the glass.
Timm isn't meant to be someone who faithfully retells another person's story.
Exactly. Even the few times his shows did episodes that were so-called "adaptations" they never copied the stories exactly. My big problem with the DTV movies is most have had similar stories done as episodes of the earlier shows. The episodes were better in every way. With even less screen time those were better focused. These things feel like bloated extra long episodes of shows that do not exist, no fully developed feature length movies.
On top of which the animation in the series were better. On those the animators had time to learn how best to work with the character designs.