Outside of some hardcore Batman fans, I don't know that Keaton's role was that highly rated.
You just aren't familiar with Michael Keaton. The upcry was more that Keaton got the role in the first place. Keaton was known for being a comedic actor and casting him was a deliberate cast-against-type on the part of Tim Burton because he wanted the character to be the star, not some big action star in the role.
Keaton is actually a very fine actor, he was well regarded in the 80s. Watch some of his movies like Mr Mom he has a presence and a distinct persona in each of his movies.
As I posted in the other thread Keaton in Batman is very similar to Downey in Iron Man. If you're familiar with each man's work you'll understand what I mean. They bring a lot of their own persona into the role. Keaton's character in Batman is a combination of the "Michael Keaton" role from his other movies + Batman. The humanity with which Keaton plays Batman that someone referenced upstream is all Michael Keaton being Michael Keatong and I think that's why the character feels so real. Bale was a great actor but he played the role with more distance... which actually makes sense in the context of Nolan's movies... he's less of an accessible character.. but Keaton's humanity is why people still connect to his portrayal after 20 years.
A way you could look at it is that Keaton's Batman is an "older" Batman. He's still determined and his wounds run deep he's but not as angry or conflicted as Bale's Batman, who is still starting out. You get the sense that Keaton's Batman is alienated but he's not disfunctional... he's come to terms with being Batman and what that means to his life.
Those 2 performances are actually quite striking to compare. They give very different feels to being Batman, but at the same time both are very true to "Batman" as an icon. You rarely get to see 2 such clear examples of 2 good actors approaching a subject in different ways. It's something striking and the kind of deep deconstruction of the art of acting you wouldn't expect from a superhero movie



You beat me to it, Payaso.