I think it's time to drop the KDE4 libraries. They were EOL months ago and most stuff that isn't yet ported to KF5 is dead upstream. This would allow dropping a number of qt4 libraries and reduce the qt4 reverse dependencies (qt4 has been EOL for 3 years now). Affected packages are:
- recorditnow (there are many alternatives available)
- ligthdm-kde-greeter (dead upstream, no signs of KF5 porting)
- krecipes (dead upstream, no signs of KF5 porting)
- kdiff3 (has been ported to KF5 for a while, just needs a release. Could be updated to a snapshot)
- pidgin-kwallet (uses kwallet dbus API, so should work with the KF5 version without any modification)
- libreoffice-still (would lose the KDE4 VCL, which is quite buggy anyway. LO-fresh has a new VCL that uses KF5 file dialog)
- amarok: it has a WIP KF5 port, but it's not quite ready and development is stalled. IMO we should let it rest in peace - I can keep a KF5 snapshot in kde-unstable for a while but it doesn't look like it's going anywhere any time soon at the current development pace. There are a few alternatives in the repos.