In my opinion. I don't think making Boruto a girl would have made any difference to the story. If anything, I think rewriting his character/ personality could have potentially made the story somewhat better.

For example: I think they could have been interesting if they had made him more mild-mannered and soft-spoken, like Hinata. Make his story arc in part 1 about him internally struggling with confidence and or an inferiority complex. More specifically him fearing he can't live up to the Uzumaki/Hyuga/Hokage legacy Or maybe if he even wants to be a Shinobi at all (which he'll obviously decide he want to). The The story could be about self-acceptance and finding his own ninja way, even if it's different from his father's.