I would appreciate a double page / spread preview for single page documents. That would allow me to work with single pages to achieve certain bleed needs (example: single printed menu card sheets that need bleed all around - but still show as double pages inside the menu book) while still being able to see the layout as a whole. That saves the time of sticking the pages together and separating them afterwards again.

This requests asks for a different approach, but I assume for the same purpose: https://indesign.uservoice.com/forums/601021-adobe-indesign-feature-requests/suggestions/31305193-auto-speads-into-pages