Some of the reasons were technical, some were very "we should be more standard."
I agree with the Python3 team, here. Mostly because it's more obvious what Python is doing now. But, it's also cleaner in my opinion.
It makes things harder, sure, 100%. But that's not always a problem or a bad thing. In this case, the more work comes with clarity and less chance for bugs (less edge cases).
http://lucumr.pocoo.org/2014/5/12/everything-about-unicode/