> The maintainers would probably do some things different with the 2to3 conversion if they had to do it over again.
Saying that "probably do some things different" is quite an understatement.
Python 2 to 3 was an articulated train collision in slow motion that spans a decade. I'm sorry to say that, but it was monumentally awful.
I really, really wish that it didn't happen because I think it kept Python back at least 5 years.
People got really burnt by this upgrade process, and the answer was "we said we'd do backwards incompatible changes". "And what, are we going to have this every few years?" one might have though.
So, it isn't enough to tell people to "stop complaining about Python 2to3" and things might be done differently in the future or past.