I don't think dialogue makes the stormtroopers more menacing. On the contrary - if they have the need to spell out even the most basic orders (blast them, stop that ship), then they really don't seem to be a really competent force.
It would be nice, however, to see some elite stormtrooper action in the movies, though. The way they are now they look like a bunch of fat cops chasing after a shoplifter.