I read through that presentation, and it mostly makes the point that the migration wasn't easy. That's something you would expect.
For instance, why would you automatically convert the svn:ignore property to a per-directory .gitignore? You can do that (.gitignore can be on every directory, but it can be on every directory above it).
It does not really state the other points that he attempted to show.
And maybe translators just don't need to deal with the version-control system directly. If translators didn't check-out the whole application, they probably never really used it as proper version control: they never really tested their translation with the latest "SVN build". So maybe translators should switch to something like Transifex.