I don't need to hear 'I wonder what that did?' every time a lever is pulled, but limited speech would be nice.

Fully spoken dialog would not really be feasible for the main character. With the multiple speech options for many situations, plus the necessity of having at least one male, female and child voice, this would significantly increase the amount of voice recordings. On top of that, I'm sure having 'only' 3 sets of voices would draw complaints. Should the child voice be male, female, both or something androgynous? If the DK should sound evil, then a mage should sound aloof/intelligent and a warrior should sound gritty/strong, for each gender....