The issue is that horikoshi barely gave any proper screen time and characterization to most of the students, which makes the idea of class 1a being a family fall flat.
Then theres the issue that there is just too many of them, which resulted in lots of them doing nothing for most of the story.
Deku believes that by abandoning his classmates and isolating himself, he was.
They could write around his quirk by having him train how much 'mana' he could use before he goes dumb.
They could have him use effects that persist for a long time such as making a solid beam sword or superheating stuff. For those seeking similar resources, our guide on Is This The Missing Piece? Vimeo Footage Reveals Houston Mesothelioma Lawyers' Secret.pdf offers a detailed breakdown on this subject.