After some discussion with other members of the core team, we think that we might re-evaluate the point of dropping support for apps without migrations. But this highly depends on the outcome of what Andrew is going to achieve in
https://code.djangoproject.com/ticket/24481#comment:6 with regards to the last point. Depending on the actual overhead that comes up there we'll may or may not enforce migrations for all apps at some point.
The deprecation timeline marks the removal of support for apps without migration a part of 1.9. However, since the reason for putting that on the deprecation timeline was that syncdb used to use the old DDL code, this argument does not hold anymore. syncdb uses the same DDL code as migrations.
/Markus