Absolutely hate the new layout - The new OneNote interface takes up way too much screen space (expansion of all the menu options on the left side of the screen takes up almost half of the display). Please offer the option to switch back to the horizontal layout, or at the very least, allow us to move the menu to the right side of the screen so that our notes don't shift every time we navigate our notebook. I understand the pressure to match competitors (such as, Notability), but to change something that already works well is a terrible move. Very annoying.
There is an option for this! I have it set to "use legacy panes" because I hate it too. I don't want half my screen to be menus so my notes are all crammed into the right half of the screen.