Steps to reproduce:
1. Install Impress in Ubuntu.
Draw is also instaled.
Only Impress is instaled. You can install Impress without Draw on Windows.
Platform (if different from the browser):
Browser: Mozilla/5.0 (X11; Ubuntu; Linux i686; rv:11.0) Gecko/20100101 Firefox/11.0
This is an ubuntu packaging issue and not a libreoffice issue, hence marking as notourbug.
Draw and Impress are highly dependent on each other and share most of their code. That means that if you install only impress, you also end up with a lot of draw installed too and vice versa.
On ubuntu most of the necessary libraries are contained in the draw package [http://packages.ubuntu.com/precise/i386/libreoffice-draw/filelist -- libsd*.so contain most of the draw and impress code]. Thus for impress to work draw is needed in order for the shared libraries the be present. The impress package then simply adds some additional files also needed for impress to function [http://packages.ubuntu.com/precise/i386/libreoffice-impress/filelist].
On Opensuse the shared libraries are all in the main libreoffice package with the draw and impress packages containing the few additional files needed specifically or draw or impress (registry entries and desktop files, and a few other minor draw or impress specific files), allowing them to actually be installed separately.)