I completely missed Stella being a glass cannon type of character, it makes a lots of sense. It also fits very nicely with the narrative since Gina and Akary train in martial arts while she doesn't, obviously she wouldn't be as good at defending from enemy attacks.
I was probably blinded by my distaste for high damage-low precision attack and played her in a mostly support role, putting the foe with the least attack output in front of her to minimize the damage she received while using Tug of War intesively for formation manipulation. Often that meant placing an archer in front of her, that she had issues hitting because of the skill difference.
Maybe a more aggressive style, using her to quicky dispatch of high health and low skill enemies, would prove to be more effective. I'll keep it in mind for the next playthrough.
Also, I noticed something suspicious: Gina can use magic and has an evil fighting alter ego and she is aided by a sharply dressed young man that arrives from nowhere, gives a few words of encouragment and disappears without actually doing nothing.
If Xici becomes the antagonistic foil to Gina that undergoes a change of heart and becomes an ally would be the last proof to my scandalous theory: Gina's Gym is actually a Magical Girl Anime in disguise!