Thinking about the more... Hiccup, sides of Hiccup, the sides of him that are still not what you'd expect from the son of a chief, the sides of him that may cause judgment, but still make Hiccup Hiccup.
Hiccup got so much stronger throughout the series, more confident, he grew into the roles that were given to him, but I think it's important to remember he's different from other vikings and that's what makes him as powerful as he is. He's still fragile, he's still scared, he's still emotional, he's still small, but none of that makes him weak, none of that makes him any lesser than anyone else, in fact, they give him the balance he needs to be the man and leader he grew up to be.
Hiccup still hates violence, he doesn't enjoy the slaughter the way other vikings do, and while that can bite him in the ass sometimes, it's also what gains him so much respect, because a man who can scare away even the most powerful of enemies while still allowing them to live is a powerful man. Hiccup still gets stressed, he still panics, he still cries, he might bottle things up sometimes, but not to the point that others do, and that's what keeps him from completely imploding in on himself, it might get him called a crybaby or a wimp, but that doesn't matter when he's still being called chief with it.
Hiccup is still the runt, his DNA demands it, no matter the beard he grows or the armour he wears, he's still small under all it, he's not one of the hulking vikings that everyone demanded of him for so long. He'll never be one of those giant men, his body will simply never allow it, but that doesn't keep him from careying tremendous strength, doesn't stop him from being that man that took down and domesticated a Night fury, or the man known for taking out others 3x his size.
So many things about Hiccup have changed since we first saw him, but so many things have stayed the same, and that's what makes him so compelling, that's what makes him so powerful on so many levels.
