supported platforms (windows xp? yes or no): we decided that it doesn't make sense to keep xp supported, nobody has such a system anymore, qt itself (angle) doesn't support it, so it might be more and more problematic to keep this running.
rework installer? Should happen.
improvements for external users, e.g. have a kf5 sdk? Not completely decided yet, it makes sense for packagers of single applications, krita/calligra might still not benefit though.
future branch setup There is some discussion going on whether to have stable branches at all. This might not be needed for our applications in the common installer, some things might become different though for packagers of single applications; especially adding new dependencies and bigger internal changes might bring serious problems in a faster release cycle.