"I am here!" Those last three words make up the catchphrase of All Might from My Hero Academia. It's simple, yet it carries a lot of meaning. It instills hope in the people who hear it; however, it's undeniably a little lackluster.
"I am Here" isn't a catchphrase. It's a generic statement. While statements can be iconic, All Might's should be exceptional; he's supposed to be the best Hero ever and the inspiration of many others. The superhero genre is full of iconic lines, catchphrases, and sayings that are easy to associate with individual heroes. MHA's quintessential Hero should have something equally unique to say.
What Makes a Good Superhero Catchphrase?
A distinct version of "I Am Here" has existed for some time. "Don't be afraid, Underdog is here." It's cheesy, but that's the nature of the 1960s cartoon from which it comes. More significantly, it's simple to identify with the hero who says it, which reveals a lot about their nature. It's also memorable since it rhymes. Might's catchphrase does not have to be corny, but it should convey a strong sense of his personality.
Another iconic line would be something like Spider-Man's "With great power comes great responsibility." Anyone who knows Spider-Man knows how important this line is to his character arc. Even if they don't, it's still a memorable line because it's good advice and no one else says it quite like this. All Might's "I am here" quote is only unforgettable within the context of MHA. Anywhere else, nobody would even realize he was being referenced.
A battle cry or similar exclamations could also help All Might. "Flame on," "It's clobberin' time," "Imperius Rex," "Shazam," and "Up, up, and away" all indicate that the heroes are ready for action. If All Might had been a member of a team, he could have said something like "Avengers, Assemble!" or "Autobots, transform and roll out!" He may possibly exclaim "Odin's beard," "sweet Christmas," or "By the hoary hosts of Hoggoth," but this would contradict the hope he wishes to impart. These phrases would provide him with something to say at any moment, not only when he arrived.
With all that said, some simple lines can become catchphrases. It could be as long as "I am vengeance, I am the night, I am Batman" or as short as "I'm Batman;" both are beloved and memorable for different reasons. It can also be a non-distinctive line like "I'm the best there is at what I do" so long as people know who said it. In these regards, faulting All Might for "I am here" is like criticizing Captain America for "I can do this all day." It's a relevant complaint, but there's more to it.
Does All Might Have a Good Catchphrase?
Technically, "I am here" is not a bad set of words. It still makes All Might out to be the Symbol of Peace he always wanted to be. The simplicity also means it can be reworked and reapplied to a surprising number of situations. What it lacks in flashiness is made up for with deeper meaning.
It's just that the phrase doesn't hold up well compared to other iconic superhero lines. Even "It's Morbin' time" would be a more iconic phrase, and it's not even real. If All Might's catchphrase had a little more panache, it would have gone down in history as one of the greats.