Several models or even individual creators could plan a whole series of different streams (e.g., different topics) and announce them over a longer period of time. This would also be helpful if, as in our case, two models are active and want to plan different streams at different times. The ability for multiple models to stream simultaneously has already been requested by another user :) But that would also be very helpful here. In addition, under "Desired Streams," you could include a comment field in the calendar or a poll asking users what they would like to see in this stream.
