So many undead bodies! My take is to drop the
DP (keep him handy, though, as one of your zombie sarges could get lucky on the boon roll [it has happened to me a couple of times now]) and replace him with two sorcerers (ML3,
SF). you will need to update to 2 CADS to do so. Roll on Telepathy on both.
Also, drop to 30 man zombie units - you won't notice a difference, and you can use the additional points to upgrade your brutes with heavy flamers. Personally, I would drop one Mayhem pack for three single Oblits (you might need to do this anyways, on account of the additional
CAD).
With so many zombie squads, you could also opt for either Huron or a zombified Ahriman (blasphemy!!) as your warlord in order to get guaranteed infiltration on at least one large zombie blob. If you go the 'Ahriman' route, you might not want the additional
CAD...Just note that zombies love to be shrouded, so Telepathy is king.
UPDATE:
I could cut down to 30 zombies if I wanted. The suggestion being to go with heavy flamers. If I did I would also sacrifice my melta capabilities.
You keep the multi meltas and just add heavy flamers to the power fists for 15 bones each. You don't lose your melta capability, but instead gain a way to deal with hordes. Note that you have a 33% chance of being immobilized each turn. If you get a good drop, you are suddenly spitting out two melta shots and two heavy flamer templates, which rocks. Also note that the immobilized result means that your opponent is hitting on your rear armor in
cc (which is where Oblits have the advantage, besides having a smaller footprint and less issue with being one-shotted by melta), so having that extra overwatch template can save your bacon. Get the best of both worlds, and take both the Mayhem pack
and Oblits.
Also: it is a rare, rare game where you will have all of your zombies swinging in combat. They will get thinned out and stretched out to the point of getting maybe half of the squad in the combat, if you are lucky. So, expect maybe 5-6 wounds on the charge, and maybe 2-3 per combat phase post-charge, against t4...Not great offensive firepower, for sure.