Although my listening area is only about 7 feet wide (we have a thin living room!), I have never really noticed a problem with sound dispersion horizontally with my VP150. I find it sounds great if I sit right in front of it, or a bit off to the side.
If it dispersed too much sound outward to the sides, then it might not aound as good. Voices would be all over the place.
Try placing your center channel slightly behind your two mains, that might help get a better, seamless pattern across the front. I have noticed many DVD's do put some vocals through the mains as well. This helps spread the voices a bit more.
