Personally, I would prefer the money and time spent on voice acting to be spent on making a bigger game world. I can read just fine, and well written text is just as engaging as well written dialog. Plus it makes it considerably easier for the modders to create new quests and even storylines.
The people who record voices are not involved in the world design process, storyboarding process, gameplay mechanics, dialog, or anything at all apart from voiceover work. So having more voice actors does not affect the amount of time or energy that can go into the development.