But any Death Guard that can carry a Power Scythe can upgrade to the Deathshroud equivalent, a 'Manreaper', and perform a Sweep Attack in Close Combat. There are many that can carry such weapons in the DG.
Which is why they wouldn't make a headlong charge without making some tactical decisions to break through. I ain't a genius like Fulgrim as he'd find some master plan to win. I'm still here. Wait... People don't sleep naked?