i'd try increasing the amount of Storm bolters in the army, have a couple of shooty DW squads (Assault cannon, SB + PW Sgt, 3x SB + PF). plonk them in somne decent cover near an objective. they may not have great range but 24 inches is still decent enough to deal with hordes (given that they usually are moving to you, except maybe foot guard with massed HWT's).
see my post here: [url]http://www.lounge.belloflostsouls.net/showthread.php?t=20145[/url]
for a better rundown of my choices.