Yoshimori is a very likeable guy, he never pays attention to his teacher, yet he is far from naive. He never let anyone takes advantage of him and as far as i know it has never been stated whether he is academically stupid or not.
Tokine is a nice girl next door, although to my dismay Yoshimori surpassed her skill.
Those things put aside, what i like about this story is that there is no overdramatization, you know the moment in which a character cry like a big baby, or cry the heart out with a sound of piano in the background.
Plus, except for few battles. our heroes need to use strategy to defeat their enemies. When the enemy is tough they will retreat for a moiment, regroup, analyze data to determine enemy's strength and weakness, form a strategy and then attack.
It's like an oasis because nowadays ,in manga the heroes leap before they think with their head first.Of course they are not a match for the enemy And in critical moment they suddenly gained a great power out of nowhere, well actually it's because of the support from their friends.