They're two completely different types of characters tbh. All Might is what makes MHA happen in the first place, he's the center of every plot point until kamino. https://twitter.com/itz_deborah/status/1294064882669649920

All Might is the one who inspires our protagonist to become a hero and the antagonist to keep moving forward. He's not just a character, he's the birth point of many of MHA's ideologies, he's basically an allegory of heroism.

But what's great about his character is that since chapter 1, we know that he's only human. He fears like everybody else, even if he's the strongest hero he can't save everyone and he's vulnerable like all humans. On top of that , we know since the beginning that he's at the end-

- of his career, and that builds up tension in the world of MHA and gives a sentiment of urgency to Izuku, that needs to learn fast so he can take his place as the "Symbol of peace"

We can now think about Endeavor's character. Why All Might shows the reader what a real hero is, Endeavor makes the reader question that. Can he be a good hero while being a horrible human being? He's the No.2 hero, but why is that?

That's why after Kamino, when he starts question his own actions and starts growing as a character, he has to prove himself not only to the people of MHA's world, but also to the reader. He has to show WHY and HOW he is worthy of being No.1

But that's the tricky part. His fight against the High End Nomu maybe worked for his public image as the No.1. But not to his family or the reader, because they know the horrible things he did. That's when his arc becomes an atonement arc. Endeavor has to change and atone.

This is such a delicate subject, and Horikoshi handles it with extreme care and competence. And that's why Endeavor's arc is a beautiful one. But it's way more personal that All Might's. While All Might server the plot as a whole, being a detrimental part of the world building, -

Endeavor serves a specific idea, that of a hero who is also an abuser and needs to change. Let's compare All Might Vs AfO and Endeavor Vs High End. Both fights parallel each other. However, AM Vs AfO is way more important to the plot that to AM, and Endeavor Vs Highend is more -

important to Endeavor individually.

In conclusion, both are absolutely amazing characters, but serve completely different purposes and follow completely different character arcs. You can have a preference, but I don't think you can say that one is a better character that the other.