Extremely important for the training goal are the average watt, which are already elegantly displayed from curve to curve at Alpe du Zwift (but can not be retrieved after training!) and at the FTP test. This is necessary for training sessions/workouts with intervals etc. LIVE! This gives a much better orientation on how to handle the current interval/segment as “more power” / “less power”! The stars after the intervals you get (or not get) do not really help to analyse your training! Also available AFTER the training and AFTER logging out! Best also a general average Watt display which is always visible.
Please search for Customizable HUD and vote it up, I will try and post the link in a little while.
Here is the link: https://forums.zwift.com/t/hud-customisation/