Sub-Playlist-Schedule by Weekday and Time
Random Subplaylists are amazing!
Even greater would be the ability to show a subplaylist only on specific days of the week or in a specific timeframe (e.g. from 12:00 - 14:00)

Generally, we try to keep scheduling options in the Schedules section, to keep things clear and separate.
On the other hand, we are planning to provide advanced actions, commands, conditions and filters for Playlists. Your suggestion could be modelled as a special command or filtered.
We will be reviewing and revert when the time is right! Thanks!