I like the idea of a shooty army but a mono-god list lacks the flexibility of being able to deal with many different threats. Beast of Nurgle for example work excelent as a meatshield to keep your squishy horrors safe from harm. Also do not forget about the warpfire rule and make sure you focus down one unit at the time or you'll be giving out FnP like candy.
On the list itself;
I'd drop the exalted flamer for starters, it really does you no good. Flamers themselves are awesome but 5 seems a little too much imho, I would rather settle for a small unit of 3 or 4 and use the remainder of the points elsewere.
Also you can't really go wrong with a Soulgrinder or two, they really are that good. The mark of Nurgle is excelent for camping in difficult terrain but the mark of Tzeentch gives it that little more survivability while maintaining it's mobility.
Aside from that I'd advise dropping the grimoire on the LoC and giving him 2 greater and a lesser reward for more survivability and so he can pack a serious punch in close combat which you really need (You're not looking for a competitive list so you won't need it).
Hope this helped, if there's anything else just ask^^.
Ps; You could try splitting up your screamers and running them as 3 man suicide squads for popping tanks, after which you can then unload an unholy amount of firepower on the guys that make it out alive^^.
Last edited by Ryu_Niimura; 01-16-15 at 03:55 AM.