"My name is Barry Allen" is the start of every episode of The Flash on The CW starring Grant Gustin. Indeed, if you google nothing at all but "Barry Allen," in google image search, the first 37 images are of Grant Gustin. You have to go about 150 pictures in until you start regularly not seeing Grant Gustin's face (hat tip to Spencer Perry on that).
So, Warner Bros faces an uphill battle when it comes to Ezra Miller as Barry Allen in their movies based on DC Comics, including The Flash. Well, one of the things that will help is if they don't try to be and do a lot of the same things. Miller himself acknowledges that in a conversation with Entertainment Weekly.
"Well, it's going to be a movie," the actor deadpanned when asked how his version would be different. "I'd like for it to be an exploration of a human being, a multi-dimensional human being," he continued, acknowledging that's a bit of a pun thanks to all those crises The Flash finds himself involved in on multiple or even infinite Earths.
"I hope to realize him as a person, and I think what’s most exciting for me in superhero mythologies is when we feel the humanity of someone who is heroic — or the heroism of someone who is a flawed, deeply human person," he said.
So, that's not so much as how it'll be different, as much as it's his general idea of superheroes and how they're portrayed in the media. Sounds a little more like a Marvel hero than most DC takes, but maybe that'll be different this time around.