Welcome to Librarium Online!
Been playing warhammer for a while, except this is my first foray into the realm of chaos! I decided that i probably couldn't go much better than a good Slaanesh Warriors of Chaos army. This army will be entered alongside a 1250pts Dark Elves army, which should look something like:
2 level 2 Sorceresses
2 * 10 Repeater Crossbowmen
5 Cold Ones
and some more I we haven't decided on yet.
My army is as follows:
Exalted Hero with Bloodcurdling Roar, Rapier of Ecstasy, Favour of the Gods, Shield, MoS.
Sorcerer with Third eye of Tzeentch, Deaths Head, Blood of Tzeentch, MoS, Lvl 2 Upgrade.
10 Chaos Warriors with Halberd, Full Command, Banner of Rage and MoS.
10 Chaos Warriors with Shields, Full Command, Banner of Wrath and MoS (Exalted Hero in here).
10 Chosen with Additional hand Weapons, Champion with Sword of Might, MoS (Sorcerer in here).
Warshrine with MoS.
My Power Dice: 2 +1 Bound
Army Power Dice: 2
Allies Power Dice: 5
My Dispel Dice: 1
Army Dispel Dice: 2
Allies Dispel Dice: 3
Total PD: 9 +1 Bound
Total Dispel Dice: 6
So, what does everyone think of this?
I think that your entire army is M4 infantry, including your exalted. Your opponent is going to be trying very hard to just keep you out of battle, and it is far from impossible. I also think that I can't believe your teammate isn't taking any dark riders. He does have some fair ranged support to offer your infantry orientedness.
He also has some solid flankers for your block troops. Unfortunately, you may find that, without much mobility or fodder troops, you find it hard to actually get your anvils/hammers together in any sort of meaningful way.
Bloodcurdling roar, you are looking at average 1 wound against things with T3, which will still get full armor save. You may want to rethink this unless you are very lucky with your rolls. The rapier is only situationally useful, and most multiwound models will have a decent strength anyways. If you are going very magic heavy, consider giving him the bound magic missile item, or, drop him altogether. His mobility really limits him, and giving him a chaos steed for 16pts could really up his usefulness, he could wait in an infantry unit, and just gain the extra armor save, or go wizard/warmachine hunting, if necessary.
If you really want that first unit of CWs to be a canopener, especially since you are giving them eternal frenzy, give them GWs for the +2 strength, it will definitely end up in your favor compared to halberds.
For the chosen, GWs will definitely give you better results than AHW, and will free up the wasted points on the Sword of Might as well. You may want to drop them down to 6 to reap back some points.
Anyways, with all those points I'm talking about getting back, or if you can gain them from losing something else, I would say you want to bring some mobility/cheap units into your army. A few units of warhounds 5 strong for 30pts each will give you a world of opportunities for controlling your opponent's movement. A unit or two of horsemen could help quite a bit as well, though they would be slightly more expensive, they also can be a moderately capable flanker, when the situation presents itself. You may want to influence your dark elf friend, as well. The dark riders are arguably the best fast cav in the game, and very well worth taking. They allow so much more tactical flexibility. He doesn't have much in the way of cheap fodder like you do with warhounds, so I still definitely suggest taking them.
All that said, this isn't necessarily a bad list, and you may do fine with it, it just has far less mobility than I personally would want.
Bloodcurdling Roar and Death's Head are not worth the points. You can't Roar while in combat and it's killing 3 models at best. Death's Head is very situational and best for lone characters. I personally don't like it as it is a one use only item, not my favorite. I do, however, like your 3 hard as nails warrior units, and the Cult of Slaanesh feel to your ally