Her growth rates are just good. 60% in speed is tied for best in the game, 55% dex is tied for second best, and 40% each in health, strength, defense, and luck are all solid, especially in any class that boosts them even a little. Cavalier plays into this, boosting her health, strength, dex, and defense growths, and penalizing her speed 10%, but her base is so high that she can handle that. Magic and resistance are legitimately her only weaknesses unless she gets rng-screwed.