I would find it quite useful if different printing configurations (for each individual layout) could be created and saved for within each project. I find that I have to save different files for A4 PDF export and A3 Booklet printing. Duplicate layouts could solve the problem but are a nuisance since they have to be edited separately after they have been created.
I know the developers have more important things to work on but I think this is worth considering for the future.