I would phrase this is a slightly different way: I think TP Virtual should have a native workout builder. Whether it's customizing existing workouts or building new ones, it currently requires using the TP workout builder which, frankly, is functional but has a outdated UI.

Having a workout builder directly in TP Virtual would solve this elegantly.

It would be a good option to customize an already existing workout. i.e. add an extra block to a proposed workout, change the watts, etc...

Do you mean create your own workouts? If so I believe they can be synced from training peaks. I’m doing mine a different way but can still import them as a .erg file into my iPad and sync with TPvirtual.

Why - there already is workout builder in TrainingPeaks?