this manga would be perfect if the MC didn't see captain's power and vice-captain's power at the exam. the story tries to tell you that he lacks common sense because he's only seen his family's ridiculous power, but also because of that the moment he sees others' power shouldn't his reaction be "why is their power so low?"
and he is a huge magic nerd and his control over magic is vastly superior to everyone (even in his family), and he comments about how "good" the vice-captain is at controlling her magic in chapter 1.1. which means he can tell if someone is suppressing their power. which prove my point about he can see the difference in power level of his family and other people even more.
this is his reaction on magic power, I haven't talked about his reaction about magic control. his first impression to the vice-captain should not be "good" it should be something like "are they pretending to be bad at controlling magic?" because that "good" should be "meh" compared to his family. And I'm just talking about his family, not him.