Since today, Okular master (i.e. 4.12) respects the margins specified in the printer setup dialog (which default to the hard-margins of the printer). This means that I'll be able to print in my printer without getting cropped stuff; yes, my printer has a default hard-dead margin of 1.5 cm at the bottom and usually files contain stuff in that area.
If your document does already contains the margins, you can get the old behaviour by simply setting the margins to 0. Also hopefully you don't have a printer that is as bad as mine and your default margins are just 0,0,0,0