Can I point out something that is making me rather bitter?
Crematorians entire thing is when a model DIES... they have a 17% chance to deal a mortal wound. An entire subfaction, that is their great ability...
Nurgle Slaves to Darkness army have a battlion that gives them mortal wounds when they are wounded on a six, no additional rolls. Plus extra damage when they attack. Plus a -1 cloud of flies bubble around their general. PLUS their abilities don't incentive you to spam a single unit type.
I did some real basic math with a dice calculator and if a unit of 40 Crem Mortek Guard somehow all got into combat with a unit of Nurgle Chaos Warriors (whatever size), the Mortek would on kill on average 5.4 Chaos Warriors. The Nurgle battlelion would then kill 7.8 Guard... WITHOUT EVEN ATTACKING. Alternatively, if the Chaos Warriors wiped out the entire unit, they would deal, on average, 6.8 mortal wounds back.
....wooo....