I'm trying to clean all of the old KDE 4 packages off my machine, but I'm having problems getting rid of kajongg and pykde4. It appears that kajongg from KDE 4 is being pulled in by kdegames-meta and shouldn't be since kdegames-meta is claiming to be associated with KDE plasma/workspaces/etc 5. The kdegames-meta .ebuild has the dependency for kajongg on the last line of the file, so I think it might have just gotten overlooked in the move to the KDE 5 slot.
KDE Applications has lots of kdelibs-4 based packages, this is no mistake. If you don't want to have kdelibs-4 based applications, you cannot use meta packages. You can disable kajongg if you set `kde-apps/kdegames-meta -python` though.