I think it mostly about disk space, as including VO for two languages would require a lot of space. Thatsaid I would much appreciate it as "free dlc" so you can download any VO that is not on the disk.
But the PC-disk already had multiple languages on it. The only thing that was missing was an option to switch between the languages. More precisely, an option to change the language in the menu. For instance, you could edit the file "BIOengine.ini" in Mass Effect 1 and change the language that way. Therefore, my little request is: If there are multiple languages anyway, allow us to change them easily
so everybody can use the language he/she is most comfortable with.
I looooved the voice acting in Mass Effect and I worship the ground that Jennifer Hale (female Shepard) walks on. The German voice acting wasn't nearly as good in my opinion. Of course, this is something I only notived after I had installed the game in German and played it for about an hour. When I realized that I wanted to try out the English version, I had to quit the game, do a Google search to find out how to change the language and then I had to edit the file I mentioned above. It was much more convenient in Dragon Age 2 and Mass Effect 3 (here it was indeed in the options menu if I'm not mistaken).
Sorry, I completely forgot about console players in my earlier post. Well, a download like a DLC for the desired language pack will do, too, as long as it is easy to use.