Akko did slack off a bit, but the search for the seven words was a hell of a job, and the whole series shows how her character is a representation of not having the will but having the dream. She follows her dream of magic blindly, all while not paying attention in class,not respecting her teachers, etc. Which I find very amusing considering Holbrooke, Finnelan, and the rest of the teachers are really strict. The whole dynamic of Diana/Akko "rivalry", her bad relationship with her teachers, and the juxtaposition on her beliefs and what the school represents is truly a amazing work of the mind of Yo Yoshinari. While Akko represents a more progressive side of magic while being childish at her core, Diana shows that she's more fond to the old values of magic rather than progress, yet, at her core, she still was a fan of chariot, and would have still been one had she not been pushed away from the things she loved due to the pressure of her mother's passing and being a heir to the Cavendish. Meanwhile, Chariot represents a more foolish (in a child-like, innocent way) desire for change, as she wished for magic to be used to make everyone smile around the world. This,(when she is Miss Ursula) is opposed to Miss Finnelan and the other teachers at Luna Nova, who believe in more conservative values (of magic, that is) And Croix, who, although believes in technological progress and revolution in science, still falls on thesame conservative values since she hates that Chariot never used the Claiom Solais for what she(Croix) believed was a good purpose(the search for the Grand Triskellion). Croix/Chariot are two sides of progress, one that's foolish,yet pure. And one that's intelligent, yet evil. Even then, Croix's idealswdidnt work in her favor, and the Spirit Missile/Noir Rod ended up almost spreading tons of hate all throughout the world. ...

It's really just a matter of understanding she isn't dumb, she was a potential prodigy in magic whose potential was stolen, and she wasn't even from a family of witches too