It would be very useful if the next/previous page buttons could be modified a bit so that when we are reading a one column document and we zoom into the upper half of the page then when we press the next page button instead of going to the next page it should scroll down and show the rest of the page. Then when you press next again it should go to the first half of the next page.

Something similar could be accomplished for multicolumn documents although in that case it would be more difficult. You may need some input from the user with respect to the template of the document. Perhaps the user can select the sequence of zoom/locations that should be showed when you press the next/previous page buttons.