Why does nobody try to make costumes look like the scource material anymore, why does it have to be "My artistic vision"?
Not being let in to the mind of the main character we see Batman from the point of view of two journalists. Unfortunately, we don't get a potential heroic protagonist here either; the entertaining and good-hearted one of the pair is quickly shunted aside for the one that falls for her subject and so loses any bite she had. Again the film misses a chance to make good use of this set-up to explore this potentially interesting figure from an outsider's perspective.
Nicholson's much lauded portrayal of the clown prince of crime also has interesting potential (such as how he sees himself as an artist), but most of his actions seem manufactured to expedite the story rather than being expressions of his personality and since this Batman is as equally crazy and extreme it's these plot contrivances that fuel their fight with one another rather than opposing philosophies. Of course not all films need to go into great depths and it is more than sufficient for superhero films to simply deliver fun and thrills, but while the Joker is a source of some entertainment the disconnect with the hero and his conflict with the villain means the film is almost entirely without suspense. In a movie that is only ever skin deep the aesthetics are the greatest achievement with the design of Gotham and the Elfman score allowing at least some avenue for escapism.
Michael Keaton and Jack Nicholson deliver flawless performances, creating the iconic Batman/Joker cinematic rivalry.