Well, in 1988/1989 they did.

From The Wall Street Journal…

Best known as a wacky prankster in Burton's 1988 comedy, Beetlejuice, Keaton has a receding hairline and a less-than-heroic chin. He stands an estimated 5 feet 10 inches tall, weighs in at 160 pounds or so, and "looks like a hundred guys you see on the street," says Beau Smith, a Batman fan in Ceredo, W. Va. "If you saw him in an alley wearing a bat suit, you would laugh, not run in fear. Batman should be 6-2, 235 pounds, your classically handsome guy with an imposing, scary image."

Not at all, says Burton. "Michael Keaton is basically an ordinary guy, a regular human being," he says. "I thought it would be much more interesting to take someone like that and make him into Batman. I met with a number of very good, square-jawed actors, but the bottom line was that I just couldn't see any of them putting on a bat suit."

This line is less than persuasive to Batman's fans. Hundreds of passionate and humorless protest letters have poured into the offices of publications that cater to comic-book fans and collectors. Many of the letter writers voice strong suspicion that Warner may pull a fast one, springing on an unwary public a cynical sendup rather than a celebration of Batman.

Warner Bros., a Warner Communications Inc. unit, is "after the money of all the people who only remember Batman as a buffoon with a twerp for a sidekick in the campy TV series from the '60s," says J. Alan Bolick, a real-estate appraiser in Suwanee, Ga. "Hollywood is just in it for the money, and Warner Bros. has been doing a bit of duplicity. I don't think Mr. Burton has any intention of making a serious Batman movie. But Batman has been part of everyone's childhood. He deserves a bit of respect."

Fans have circulated petitions demanding a different cast, and they booed Warner representatives who had the audacity to show up at a comics-fan convention with a photograph of Keaton. A few fans also dislike the casting of Jack Nicholson as the Joker, a pathologically evil Batman archenemy. Mr. Nicholson, it seems, is guilty of having a sense of humor.

"How can you have Jack Nicholson playing a villain and not have him be funny," says David McDonnell, editor of Starlog magazine, a monthly devoted to science-fiction media.