i am having a very similar issue but with powerpoint 2010 and 2013. for the longest time everything worked perfectly, and then it must have been a windows update or something that broke it.
my process:
go to visio diagram and select the page i want to copy
select all - copy diagram
go to powerpoint 2013 file - select slide
paste special -> paste link as: microsoft visio drawing object (only option)
the diagram comes in with everything on the right side cut off or cropped.
dragging the corners and resizing does not help - doing that only expands or shrinks that cropped object.
unlike in Word, i do not have the "Crop" button when i right click the object and cannot expand it out like you can in word 2013.
any ideas on how i can get do a linked visio paste special AND have my entire diagram in powerpoint 2013?
thanks!!!