I've been using Illustrator since 1988 and always enjoyed the use of the keyboard 'cmd opt (alt) spacebar' to zoom in and out. Its good to see the same commands in use with Publisher.
But there seems to be a slight glitch. At the moment when i press 'spacebar', the hand appears; then 'cmd' and a '+' appears to zoom in; then 'alt' key and the '–' appears to zoom out. It did work once to zoom in and out, scrolling with the mouse, but now the '+' will only let me pan the pages and not zoom in. If I then add the 'alt' key to the 'cmd' and 'spacebar' I can zoom in and out using the mouse scroll function (but the symbol remains as a '–' negative.). I would suggest panning is only with the 'spacebar', zoom in with 'cmd spacebar' and zoom out with 'cmd alt spacebar'.