It would be helpful if we could predefine a general width for a given page, just as we now can for the page header.
At the moment I am (ab)using the container element to basically do that. We use “Large” a lot. So I set the container to “Large” so that I can then place smaller elements inside the container.
If I did not have to do that, I could actually use the container to a greater potential, by using “50%” containers for example and then placing smaller elements inside those 50%.