i dont think both changes are equally drastic. not even close imo.
Both are characters merging. Both change Batman's origin.
ras has always tried to groom bruce and tried to convert him to his cause. and he has often been a sort of anti father figure to bruce.
now ras has never been the one responsible for training bruce but even in begins he is only one element of his training (albeit a big element) and the inclusion of ducard as mentor persona is at least marginally faithful.
Ras in BB was THE most important trainer and shaper of Batman. He instilled in him to become a legend and a symbol based on fear. Nothing of that happened in the comics. Not to mention that Henry Ducard is not Ra's al Ghul. That 's plain unfaithful.
the joker on the other hand is a huge departure not only because it negates the real reasons batman and joker are arch enemies by creating this artificial fued but it directly effects batman's genesis by changing the nature of the crime against the waynes. in every incarnation of his origin bruce's parents are gunned down by a common thief. a completely unspectacular crime from a decidedly common source with common motives.
The nature of the crime was not changed at all. In B89 it was still a common thief (Jack Napier before being a crime boss that doesn't need to assault people on the street) killing the Waynes in a completely unspectacular crime (common street assault) from a decidedly common source with common motives (to get their money and possessions).
by making it that the waynes are murdered by someone who goes on to be anything but a common crook (and coincidentally his greatest foe) it severs batman's ties to the common criminal that he originally waged his war on in the first place and makes his origin a plot convenience.
No. When Jack Napier killed the Waynes he was just a common thief, as the canon says. What happens with him years later is another story and doesn't change the nature of the event at the time it happened.
Young Bruce Wayne becomes Batman trying to stop the common criminal because it was such who killed his parents. It is only YEARS later that he finds out that 'that' common criminal became the Joker. He obviously didn't know that when his parents were killed nor he knew throughout all those years until he became Batman. In fact, he operated as Batman against the common criminal (like those two robbers on the rooftop at the beginning of the movie) for quite some time before he finds out that the common criminal that killed his parents bacame the Joker.
for the record i think its works well enough in the context of burton's film but changing the nature of batman and jokers relationship is much more drastic then what the filmakers did to ras in begins.
It only changed the nature of Batman and Joker's relationship at the end of the story. Throughout the movie they hated each other because of the same things they have hated in comic books: Joker hates Batman because he blames the cape crusader of falling into the vat of chemicals (just like in The Killing Joke) and because Batman represents the authority and is "getting all of his press". And Batman hates him because Joker represents the chaotic crime that one day took the lives of his parents.
Then, at the end of the story, Batman finds out that Joker killed his parents, but before that their relationship was not based on that fact (unknown to both of them).
All the same, Bruce's relationship with Ducard is close to the comics during most of the story and, again very similarly to B89, at the end of the story he finds out that Ducard was Ra's and that he was closely involved in Bruce's parents killing.
That's why I say they're both as drastic.
