I'm guessing that the creators don't add full voice-overs because they figure that people don't want to hear the guys' dialogue, even if the women don't really have too much to say.
is there a link to download the horikawa goro motion comics? i've been looking for it since i found out about it. i would buy it but my japanese has degraded to such a point that I can't even figure out how to from that site that was linked.