Move the page layout from the page to the page style.
There are many reasons for this.
Sure, we lose the ease of use we had previously: the user could change the layout of any page when he wanted.

But :
1- This couldn't be saved in OpenDocument files without heavy broken hacks
2- Documents using the right OpenDocument way of doing things couldn't be adapted to this scheme.

(I still didn't look at the saving code for page styles, but it will never be worse than before)