I was just fiddling about with these 2 different file types, and noticed that in full screen, Pages thumbnails appear on the left against a grey column, whereas PDF thumbnails appear on the right, against a white column. I wondered why the difference, and personally find the former implementation much nicer to look at.
Pages documents are (usually) displayed by Apple’s Quick Look plugin for such documents and the thumbnails are part of the plugin.
A little OT but it involves PDF display. If I choose to view PDFs at 100% I wish that setting would remain after quitting and re-opening DT. It always defaults back to Zooming.
Something small, but annoying!