One can easily make the argument that storytelling is fully dependent on rich, full characters. Great ones can make us cheer when the hero wins in the end or bring us to tears when they lose. Strong personalities can organically inform decisions that, in turn, create realistic plot points and keep the story moving. If the audience doesn’t care about the protagonist, they have no incentive to keep paying attention. It’s because characters are so vital that ensemble movies make for a terrific challenge.