My suspicion is that the script-in-development-hell idea might be true. While the whole notion of a "magical academy" is fairly common (there have been multiple such series in recent memory), the series tends to break with the Addams Family mythos with an explicitly magical world rather than an implicitly magical world.

That is, in previous incarnations of the Addams Family, they're weird and they're like these various horror/magic archetypes, but they tend to exist in a (mostly) grounded reality rather than one where everyone just blithely accepts that vampires, werewolves and merfolk simply exist as an entire cultures - or that you've got mystical powers such as precognition and telekinesis as every day occurrences.