Warlord Traits for Slaanesh Daemon lists

Ed note: This was completed in September 2014 to accompany my article on Daemonic gifts, but sat as a draft mistakenly.  I'm finally publishing it.
Introductory text

Potential Warlords
Herald on foot -

Herald on steed - A herald on a steed is always going to take either the loci of beguilement or grace.  This makes them very fast and very dangerous.  They are my initial wave.  Making them the warlord can potentially increase the killability of the seekers they ride with.  Unfortunately, they will almost always die.  This makes them a liability

Keeper of Secret- A KoS is the Slaanesh GD.  There is, unfortunately, no named GD outside of gargantuan FW models.  They have an impressive statline with 6 wounds, T6, S6, WS9, and I10 but with only a 5++ they rely on greater gifts to increase their survivability.  If you can get invisibility on them, they can survive, but otherwise, are very fragile.

Be'Lakor - Be'Lakor comes with Herald of Doom, which causes all units to take Fear tests at -1.  So many armies ignore this that it is not a great trait. While Be'Lakor is very survivable, he is by far the biggest target on the board.  Against armies with extensive ignores cover he won't live very long.  I generally prefer not to make him my warlord for that reason.  I don't want to give my opponent any extra reason to target him.

Combining with Warlord Traits
 The rules for gifts say that they are determined at the same time as warlord traits.  So you get to choose which you roll for first.  This is especially important for greater rewards, which provide defensive buffs.

If you take a CAD, you can re-roll your warlord trait, which helps to avoid some of the more useless options

Command Traits

1. Friendlies w/in 12” use Warlord's Ld - Not very useful for heralds at Ld8, better for a KoS at Ld9.  This would only really help when taking daemonic instability tests, otherwise, Daemons don't take Ld tests often enough for this to be worth it.
2. Enemy units within 12” use lowest Ld - Could be useful since every unit has fear and you want your leaders mucking it up on the front lines.  I find that this really doesn't do much in practice though whenever I've gotten it with any army.
3. Friendlies w/in 12” have Move through cover - Move through cover is nice as it gives you the option to move through terrain that blocks you.  With a built in 5++, you don't need cover as much as LoS blocking.  It would be great on a steed herald with the loci of beguilement.  The KoS already has MtC.
4. Friendlies w/in 12” add 1” run and charge - Zoom.  Makes Slaanesh even faster.  This combos nicely with fleet.  I'm not complaining about this one.  Against nearly any opponent it is solid because it adds reliability to charge range.
5. Friendlies w/in 12” re-roll 1s to hit shooting - Heralds are BS6 already and rarely have shooting attacks. A keeper who takes the Lash of Despair could make use of this, but otherwise it's the least useful on this table.
6. Friendlies w/in 12” re-roll 1s to hit in assault - Potentially really good considering the high WS of Slaanesh.  The bubble effect is really nice as well.  Could lead to overkill during assault though, but you'll really hit their lines hard with this.  Ideal for a herald with the locus of grace, since beguilement already gives full re-rolls (but not a bubble).  Really nice against a high model count or assault based army.  Great for challenges as well.  Don't forget if you have an etherblade you'll reroll ones, then get a free reroll of a 2 (or 3).  This is the best roll on this table for a KoS.

Roll #4 is good in pretty much all lists and I'm happy enough if I roll it.  Roll #3 is good for a non-beguilement herald while #6 is better on a grace herald.  A keeper wants 6, 4, 1, 2 in that order, but I don't think I would ever roll on this for a Keeper.  This could be a good table to roll on for a herald if I'm undecided, but the risk is there for a dud roll depending on the warlord.  It has a higher floor and lower ceiling that the other tables.  Nothing that really stands out.

 Personal Traits

1. Warlord has counter-attack - At least counter attack extends to the whole squad.  Can help mitigate a failed charge, but you're still going to die from getting shot first.  Against another assault army, it's definitely solid.
2. Warlord has Furious Charge - Pretty sweet stuff for deamonettes and seekers, even the KoS will find utility against vehicles with it.  This is the best roll on the table in my opinion.  Doesn't help as much with vehicles (for infantry) as you would think since you still need a 6, but now it would be an auto-pen against rear armor 10.  It helps them tremendously against walkers, infantry, etc.  It doubles the wounds against T5.
3. Warlord has outflank - All daemons can deep strike already.  All heralds on steeds can outflank already.  I'm not sure I would want to outflank foot daemonettes.  Strictly worse in every way than Master of Ambush (strategic #3) as infiltrate confers outflank.
4. +1 VP for each char the warlord slays in a challenge - Slaanesh is very combat oriented so this is a great fit.  It doesn't have to be the enemy's warlord or even an IC, just any character will do.  This is a fantastic combo with a Loci of Beguilement since it lets you choose who will take the challenge and they can't refuse. 
5. Warlord has FNP - This is great for a KoS but not so much for a herald.  It's not terrible, but a 2 wound, T3 herald won't get nearly as much use out of it. At 5 wounds, with only a 5++, the KoS needs all the help staying alive it can get.
6. Warlord has Fearless and It Will Not Die - Fearless will help avoid DI tests and let you tie up an imperial Knight or other deadly units.  IWND is less useful for a 2 wound T3 model that will get instant deathed more than it will ever recover a wound.  Alternately, Keepers love IWND, but you may already get it from a gift.

For heralds you have some really great options here with #2 and #4 being great but #5 & #6 are good. enough.  Roll #1 is situational, but #3 is pretty useless.  I wouldn't re-roll 5 or 6 though to try for 2 or 4.

Keepers should roll their gifts first to see what you end up with. since some of those rolls are straight up better version of what is offered here (e.g. FNP 4+ instead of 5+).  Overall, this may be the best table for a GD and I've even been favoring it for Heralds.

Strategic Traits

Since you now know if you're going first or second before you roll, this table is even better than before and gives you some good options.  For the most part these aren't going to make a difference between using a herald or keeper.

1. All units have Move Through Cover and Stealth in ruins -If there are large center blocking ruins this is a cool.  Run up to the center hide for a 3+ cover save, then run through and try to charge the other side.
2. Can activate Night Fighting and have Night Vision - Night Vision isn't going to help a whole lot since there is almost no shooting with Slaanesh besides the occasional gift, warpfire, or harvester cannon.  Stealth on all your units for the first turn is great and helps you get in position for a turn 2 assault.  Tau ignore night fighting so this will do nothing for you.  I'll always ask for the night fighting roll and on a 4+ you'll already get most of the benefits.
3. Warlord and 3 non vehicles have Infiltrate - You can never charge first turn for a unit that infiltrates.  This is going to depend on the terrain.  Slaanesh doesn't have alpha strike capabilities with this trait seeing as they really have no guns.  Very worthwhile if you go first, for the simple fact that you can hold off deploying units until you see what your opponent is going to do.  Too bad it doesn't work for the Soul Grinder.
4. Add +1 to seize, can re-roll reserves (while alive) - Seizing is always nice.  I'll keep this if I'm going 2nd, but probably not if I'm going first, since I won't want to keep anything off the board to start.
5. Opponent has -1 to reserve rolls - Situationally useful against a reserve heavy opponent.  It is more useful when going second or against a flyer heavy army, Grey Knight Nemesis Strike Detachment, or several Tau builds.  It can alter opponent plans. 
6. Choose 3 units to take a pinning test their 1st turn - Pretty sweet deal against Tau with their low leadership or other Orks to maybe cause some early mob rule wounds.  Since pinned units cannot snap fire anymore, it gives you a chance to suppress some enemies.  Won't have any effect against Daemons, pure bike armies, mech forces, Knights, Necrons, or Tyranids in synapse.  That still leaves a lot of solid armies and options that you'll want it against.  It could be just enough to disrupt someone's plan, but probably not.

I love strategic for my orks when I get an extra trait due to da finkin' kap.  For Daemonettes, I'm pretty lukewarm on this, it would be my last choice to roll and many of the traits are too easy for my opponent to work around.

Daemon Traits 

1. Melee weapons have instant death - Slaanesh heralds are WS7, I7, with 4-6 attacks and the ability to get an Ap2 weapon at initiative.  Since they come with rending, any attack of a 6 is already AP2 and can wound anything, regardless of toughness (hello wraithknights).  This turns the herald into a massive target because they are so terrifying.  As an Ork player, having no invulns in cc, this is pants crappingly scary.  Works better with a steed since you get the bonus attack.  For a keeper at Str6 it will wound most enemies on a 2 anyways and tear through multi-wound models or ignore FNP that can't be denied (like force).  If I roll this I'll probably make a big show of it just to psych out my opponent.
2. Warlord and unit have Hatred - Useless on a loci of beguilement herald, which already gets full rerolls.  For a grace herald or grimoire toter, this is very nice.  Really nice for a keeper who can't take a locus or be joined by a unit.
3. All enemy units -1 to fear tests - This is what Be'Lakor comes with by default. Against many armies it will do nothing.  Space Marines have ATSKNF while Daemons have Daemonic Instability, and Tyranids in synapse are fearless so won't have to roll for fear tests to begin with.  Tau are almost all WS2 so will be hitting on 5s already so WS1 does nothing.  Necrons are mostly WS 2 as well, wraiths are fearless, and they are almost all Ld10 and unlikely to fail on a 9 anyways.  It will rock against Chaos Space Marines, Orks, and Dark Eldar are the ideal target to help limit return damage.
4. Units w/in 12" re-roll failed instability tests -Daemonic instability tests are brutal.  What I don't like is that wounds aren't necessarily a good measure for how successful a combat was. If I charge a squad of terminators with daemonettes and kill 3 of them and they kill 4 then that's a huge win for me.  I just killed 120pts of terminators and only lost 36pts in return, yet somehow I lost the combat.  Trying to calculate how much each unit is worth would be far too cumbersome, so I understand the mechanic, I still don't like it, but it's worse for Orks, so I can't complain too much. Re-rolling will help you pass or minimize casualties.  I wouldn't re-roll this.
5. Re-roll warp storm table -Rolls 2, 3, 4 really suck.  Rolls 10, 11, 12 are really good.  This will decrease your chances of the former and increase your chances of the latter.  To play safe, I wouldn't reroll a 5-8 either.  Khorne's wrath (#9) is only a small blast and I get to choose who it goes over.  I don't think I would reroll this in most cases since I do want to cause Str8 hits to my enemy and it's worth the risk.  This trait is insurance.  Don't count on it to help you out, just hope that it can help you avoid a disaster roll.
6. Daemons deep striking w/in 6" do not scatter - Essentially an icon.  It works regardless if they are the same alignment, but still it's just an icon.  It does work for summoned units so that's something, but for the most part it's not going to be very useful.

One of the better warlord tables from a codex. Roll #5 is the best roll for an all-comers list, since sometimes you really don't need additional killing power.


Conclusion
Personal is my go-to table lately especially against a space marine list or anyone you know isn't strictly running away from you.  When facing heavy shooting lists, strategic could be useful, but you need to consider the opponent, table, and mission carefully.  If you can't decide then the Daemon table is fine and the command table can be useful for the movement bonus options.