Thank you for the answers!
As far as I see I am not alone with the wish to spend my time with developing Pywiki (which I didn't do since dropping SVN) instead of preparing for developing and finding out annoying technical details.

2014-11-14 20:12 GMT+01:00 Andre Klapper <aklapper@wikimedia.org>:

https://www.mediawiki.org/wiki/Phabricator/versus_Bugzilla lists the
reasons for the migration. It also links to the "Past steps" of the last
12 months which lead to the community's decision to move to Phabricator.

I don't want to complain more, just for the log: this decision was not that of Pywiki community. We were just glued to MW community and their preferences.