I guess this is what makes MHA so confusing for me. I really am just at a loss as to the appeal of Deku. He doesn't really have much of a history. He has no significant familial ties or friendships. There's not a lot going on there emotionally or intellectually, and his goals are simple minded. The vulnerabilities that he does have seem like concessions created to let a very general population have an easier time relating to the character.
Deku is pretty smart actually and there's a number of cases in the manga where he outthinks someone or is able to analyze things resulting in a beneficial outcome.