Many of our less experienced users get confused when they cannot see a sub grid before the record is saved for the first time). e.g. "Where do I add the Opportunity Products????"
The same with the Business Process Flow "Where did the Next Stage button go???"
for the BPF: Show a button saying "Save record" and when clicking it saves the record and then displays "Next Stage"
for subgrids: instead of hiding the Subgrid all together which also changes the layout of the form significantly, show something similar to what is happening now on the new Timeline that tells the users to save first to access it.