Michael Keaton looks NO MORE like a comic book Batman facially than Val Kilmer, Christian Bale, George Clooney, or even Adam West. If you have any sort of jaw, under a Batman mask ... you will look like a Batman from the comic book page. So as Michael Uslan also said, it's basically irrelevant who plays Batman. Batman the character and the costume does most of the acting for you. It's who plays and looks like Bruce Wayne that counts.
Bruce Wayne is just a mask. "Bruce Wayne died when his parents got blown away." - Frank Miller. It's Batman that really counts.
And in that category, out of everyone ... Michael Keaton comes the least close to representing the character.
Michael Keaton is a great character actor and represented the Bruce Wayne role well. Michael Keaton was great at contrasting the character from the laid back, joking and unassuming public Bruce Wayne to his dark and brooding Batman. Bale also contrasted between the public Bruce Wayne role to the dark brooding Batman well.
Also if you're going to quote Bob Kane, please don't ... because after each movie he hyped up every person to don the cape and cowl to be a better and better representation of his creation. So he either had a perpetually changing idea of his original creation, or he was in the business of selling ... which I believe to be the latter, cause he even gave Clooney the props for being the best Batman / Bruce Wayne before he passed.
Bob Kane's opinion did not change. Bob Kane said Keaton transformers with that cowl on and had that Batman air about him, Kilmer and Clooney looked like his comic book Bruce Wayne. "When they first represented him to me as the Batman, I was a little bit surprised and almost disappointed - originally. Michael (Keaton) doesn't have a big build, he doesn't have a strong, chiselled face, basically. Somehow, when he gets into that uniform, he becomes the Batman. He becomes swashbuckling, he has an air about him. The chin juts out another inch with that Bat-cowl he wears; he looks strong, he looks like Batman." Bob Kane stated that he felt Val Kilmer looked great as Bruce Wayne because "Val Kilmer has a strong chin and is tall, dark and handsome." Bob Kane stated that Clooney "looked the most like my comic book Bruce Wayne. He has the squarest jaw. Looked the most elegant and suave and handsome as Bruce Wayne." Kane said, "I personally like the dark, brooding Batman better. And in the first year, before Robin, Batman was a lone vigilante, dark and mysterious - like the two [Burton] movies. So if I had a choice, I like the dark mood - although I like the campy TV show, I thought it was great fun. And still is. It was a marvelous spoof, but certainly wasn't the definitive Batman. There are parts of the first movie that I like better, and parts of Batman Returns (1992) I like better. Tim Burton has a very film noir look to his films, they look different to any other film by any other director. They almost look like German expressionism. He gets a certain look that no other director has. He was once an animator, as I was, and he's visionary, he understands the frame, what looks good on the screen."