You know what else isn't canon? A Joker who wears clown makeup. A Bane who doesn't us the super steroid Venom. A Batman who's grounded in reality. The Batman I know has gone toe to toe with likes of Darkseid. Somethings Nolans Batman will never do.
There’s a difference between the letter of a thing and the spirit of a thing. Nolan’s Batman is in keeping with the spirit of the comics. It may ground Batman in a reality more like our own than the DC Universe, but that doesn’t change the essence of the character. Burton makes Batman a maniacal slaughterer of anyone who stands in his way, even when they pose no threat to him whatsoever.
Burton’s Batman is a cruel billionaire beating up (and often outright murdering) people for ill-defined reasons. The death of Bruce’s parents is touched upon only in vague flashbacks, and not given psychological weight. This is a huge mistake, because the first thing we have to accept about Batman is that his psyche has been stretched to the point where his best option is fighting crime dressed as a bat—and burton never even tried to sell it. He’s much more interested, oddly enough, in telling a Joker origin story. The Joker’s past, in my opinion, should never be clear. DC has made attempts to give him a defined origin, but none of them really stick. The Joker isn’t supposed to have defined past that explains everything about him. The character is supposed to be complex and mysterious to the point of overwhelming us. Burton just turns him into a mob enforcer who just happened to fall into some goop.
Can it be argued that Burton’s approach is superior? Yes. But you’ll never convince me of that. Nolan’s vision of a well-defined Batman opposing a Joker whose past is a complete mystery, to my way of thinking, more accurately reflects the essence of those characters. Burton’s vision, wherein a bland and probably psychotic playboy dukes it out with a mangled crime lord with a flair for the dramatic, just doesn’t do much for me.