Yeah, it'd be interesting to know why the change was made, particularly if Bill Finger himself made it.
Its worth remembering that Earth Two is in itself a kind of retcon/reimagining of the Golden Age into a cohesive continuity and universe (which those old stories, for the most part, really did not help with). The actual published Golden Age (and early Silver Age) stories were loaded with inconsistencies and changes, so in the 70's and 80's, writers were basically free to pick and choose details and craft their own vision of what the 'Golden Age' was supposed to look like.
And that's why this issue has Martha Wayne dying of a heart attack and Batman starting out wearing a slightly modernized version of the classic Golden Age/early Silver Age suit, rather than Bob Kane's original design with the purple gloves. And also why Stryker falls into the vat of chemicals by accident, and not due to Batman punching him (Bronze Age writers tried to water down the idea that the Golden Age Batman used lethal force).
Oh I agree. But I was talking more from the point of view that the powers-that-be felt that the murderer never being found would be more in line with with their ''darker and grittier'' take on the Dark Knight.And in BATMAN 47, Bruce only catches Joe Chill years after his parents' murder, after he's become Batman and after he's teamed with Robin. So if not catching the killer was a rationale for him being a broody pillock, then he should have been morose in all those 1940s comics and he wasn't. Personally, I think that Bruce would not have been so backward in finding the man that snuffed his folks and it's more likely that Chill was brought to justice earlier.
As far as Chill being brought to justice earlier goes - I'm cool with the idea, which seems to have been the standard since Batman Begins (and since Chill was reinstated to continuity after IC). But personally, I feel no story involving Joe Chill has ever matched the poignancy of the original - the idea that Bruce fought crime for years as Batman and became the world's greatest detective, but never found his parent's murderer, but one night, by happenstance, he just so happens to get involved in a case where he encounters the man again and has a chance to bring him to justice in some form. Not to mention, Bruce revealing his identity to Chill and haunting him, Chill blabbing that he created Batman to other criminals who gun him down...karma at its best! (The BaTB cartoon's adaptation of this story is a true gem, I might add).
I also kinda like the idea that when Bruce helps Dick bring Tony Zucco to justice, he does so because he wants Dick to have the closure and sense of justice that was denied to him. Until he later gets his chance as well.
But I'm not adamant about it. If anything, Joe Chill being caught even before Bruce puts on the cowl adds a bit more complexity to Bruce's decision to become a crime-fighter beyond him just wanting to lash out at the world owing to his parent's murder.