I’d love to be able to create a workout and save it. As a bonus I’d like to be able to do this while at work on my lunch break (ie log into my Zwift profile, create my workout(s) for the day/week and save them. This could start as a simple 3 column table (duration, erg/resistance/sim mode, %FTP / %Grad) and then grow pending user popularity.
An option for Zwift to benefit is for there to be a “share workout / training plan” function - that way the Zwift community could populate your workout portfolio for you!