It’s not an easy question, but my answer is going to be “yes”.
A comicbook heros story is told over decades and with time maybe centuries. Making sudden huge changes to characters whose stories are told over such timespans is not unproblematic. Imagine a reader investing 30 years of money and time into following that character, then at a single writers whim, something drastic happens to that character that makes it unpalatable for the reader.
The killing joke is arguably a potentially unpalatable tale not in line with what Batgirl readers might have been looking for.
Oracle is a great character, I,m not going to debate that. But why not make it a new character, with its own origin story? Short term, the shock value of it being a character you are familiar with will be important. Long term, not so much. The Oracle stories would have been just as great if Oracle was a new character.
Because of the decision to make it the same character, you estrange original Batgirl readers, and you upset Oracle fans when you inevitably return Barbara to the original character again.
These are issues that will linger forever. I am still meeting people angry that the Killing Joke was ever made. I still here people bemoaning the lack of Oracle ongoings.
In my mind it wasn’t worth it for one story. It would have been better long term if we had Oracle and Batgirl being different characters and let both find their own fans, and had them both on the active roster. Then everyone could have had what they wanted.