> My guess is that most people who prefer zero-based feel strongly about it, and most people that like one-based don't care that much.

FWIW, as someone in the latter category (liking one-based indexing), I'd say you're partially correct: I'm not emotional attached to 1-based indexing the way some 0-based folks seem to be, but it's a practical nicety and one of the things I'm really glad Julia chose to do. Making 0-based the default would definitely reduce its appeal to me.