This is a very good point. Ellington lived a quiet and sedentary life for many years, and throughout ATWQ her overriding goal is to return to that way of life, to set back the clock to an eternal childhood. Ellington as a shadowy trickster is not her natural state, though it might be her true one.
And coming to terms with that fact, because whether she wants/realizes it or not she is VERY good at being a trickster, and whether or not she wants to embrace that fact could take up a huge chunk of her time post series. I like how with all of these theories Ellington never escapes that trickster aspect, whether it's a constant in her life or not.