It would be great to be able to select a number of widgets and convert them to a master screen (creates a new master screen file somewhere of the selected widgets) and also uses it in-place at that spot. The UI would be similar to creating a group, but I would be creating a master screen instead.
Additionally, it would be good to select a number of widgets in a screen and automatically replace them with an existing master screen at that spot. I would select the widgets, choose to replace them, and I would be prompted for the master screen to use instead.
The reasoning behind these ideas is that I tend to redundantly copy and paste the same widgets into a number of screens, then (in hindsight) I need to make changes (to all of them). To save time I put the widgets into a master screen so that I don't have to make changes in multiple places.