6. Overly Convoluted Mythology
When was the last time a Young Adult novel introduced a world as compelling and unique as Harry Potter (a film I hesitate to mention in this list even in a positive light for how gracefully it avoids all these cliches) ? Generally, Young Adult literature features what is essentially watered down versions of more complex and philosophically challenging worlds - even The Hunger Games, still a massive standout in this category, is itself a thinly developed dystopia when compared to that genre. There are various reasons for why this tends to be a liability. One possible sub-reason is in the focus - if the story seems more interested in the smoldering melodrama than the fantastical setting, Young Adult films give no incentive for the audience to care about their layered mythology - which invariably has more plot holes than one can feasibly keep track of. Ultimately, the audience has to ask themselves: "Do I care about the story enough to stick around for the mythology?" and if the film has not given you enough reason to soldier on, they need some lessons in world building from a certain J. K. Rowling.