Well, figured I'd actually throw a post out. I've been playing a lot of Conquest, and generally as new Warlords come out, I give them a shot, so when the Scourge finally dropped, I immediately tried out Ku'gath. The deck I've been running is this:
1x Ku’gath Plaguefather (The Scourge)
Army Unit (29)
2x Black Legion Heldrake (Core Set)
3x Chaos Fanatics (Core Set)
3x Heretek Inventor (The Howl of Blackmane)
3x Khorne Berzerker (Core Set)
4x Kugath’s Nurglings (The Scourge)
3x Shoota Mob (Core Set)
3x Splintered Path Acolyte (Core Set)
3x Vicious Bloodletter (Core Set)
3x Void Pirate (Core Set)
2x Xavaes Split-Tongue (Core Set)
3x Dire Mutation (Core Set)
2x Rune-Encrusted Armor (Core Set)
1x The Plaguefather’s Banner (The Scourge)
2x Fetid Haze (The Scourge)
3x Promise of Glory (Core Set)
3x Tzeentch’s Firestorm (Core Set)
2x Warpstorm (Core Set)
1x Fortress of Madness (Core Set)
3x Ork Kannon (Core Set)
1x Vile Laboratory (The Scourge)
This feels pretty standard for him at this point. Some comments, however.
Black Legion Heldrake is one of those cards that when dropped, can completely change the game for your opponent. Imagine having a Bloodied Warlord, and knowing that you need to win the next battle at a planet where the Heldrake is sitting. That's an awful position to be in. What's nice about Chaos is that you can often get the Heldrake out! Either winning at Yvarn (if it's available) will do it (Ku'gath can certainly win any planet he wants early game), or using the various cultists to play him from your hand at a discount. Either way, despite its cost, the Heldrake does make it to the table.
People on cardgamedb seem to prefer the Ravenous Flesh Hounds to the Black Legion Heldrake, but I don't find myself wishing I had the Flesh Hounds in my hand when I draw the Heldrake. There are corner cases where the Flesh Hounds would be better, however, but against some factions, the Heldrake's Flying will be nearly impossible to get around (I have yet to kill a Heldrake with Ragnar, for instance).
Chaos Fanatics, Heretek Inventors, and Void Pirates are generally used only for command. Sometimes my opponent has put the Inventor at an early planet, but given the very Aggro focus of this deck, that's perfectly fine.
Khorne Berzerker is a late, but handy addition. First, he's a prime target for the Rune-Encrusted Armors... but the huge advantage is that with Ku'gath, you can power him up conveniently.
Xavaes always seems to be worth it. Put him down where a major battle is about to happen, and you'll generate so much economy you'll have no issues affording that Bloodletter or Heldrake.
For Attachments, I've considered dropping the Rune-Encrusted Armors for Promotion, because Chaos has such a difficult time at times with the command struggle. But in every game I have draw it, the Armor has actually been a tremendous hindrance to my opponent, generally on the Berzerker or on Split-Tongue. Two extra HP can be tough to prepare for (especially if I deploy it later in the turn), and the extra attack is a great bonus. Dire Mutation is an amazing play as an Ambush, making it extremely difficult for your opponent to plan how much to shield on their most important units. If they shield an attack to leave them at 1 health, and you attach Dire Mutation as your next action, you've ruined their day.
The Events feel obvious; almost every Chaos deck seems to run these. Promise of Glory is basically just a type of economy.
For Supports, I have to say that Ork Kannon is an incredible, incredible boon to Ku'gath. Your opponent may foolishly attack other Chaos units at the planet to avoid putting damaging on Ku'gath, which he could then transfer as (unshieldable) damage. Ork Kannon not only provides Ku'gath damage to redistribute as 'gifts', but also puts additional damage on his units! Win-Win! I've also used them to drop Command units sitting alone at planets. As I've mentioned, the Command struggle is tough for Chaos at times.
I had built this deck pre-Gift of the Ethereals, but I haven't made any changes to it after its release. Some thoughts on cards I could include though...
Ammo Depot is one I have considered (and still consider). In several games, I have dumped my hand VERY early in the game (usually to win a planet or two), and have resorted to top-decking. This would help me keep that momentum going. I feel like I would need to drop something to include this, however, and at this point, the best bet is the Fortress of Madness. I may play around with that.
Despise does not strike me as particularly useful, as I have plenty of more direct kill options.
Goff Big Choppa seems like a great card, but I couldn't see using it here. I do like having Armorbane, without a doubt, but I find the extra resilience provided by the Rune-Encrusted Armor is often a bigger help than the additional offensive punch. Ku'gath can generally grind down opponents himself- I just need things to stick around long enough to help him.
Nurgling Bomb is a tough one. I love it, as it is a very thematic inclusion. However, I don't have so many Nurgle units to make it very one-sided (my Nurglings tend to get used only on the planet I need to win, or as a command unit), and the cost doesn't really make it attractive, even for its additional flexibility.
Rotten Plaguebearers are a better choice with Zarathur in my eyes. They do add an additional aggro push to this deck though, so I may try swapping them in for one of the various command units I have.
Sslyth Mercenary. I don't find this card good in any deck, let alone this one.
Throne of Vainglory. One of the guys I play with is trying to build a deck around this card with some interesting results, but it's definitely not a card you can just throw in and expect to get a benefit from. Not a good inclusion here.
Well, there you have it. As I play more with this deck, and make changes to it, I'll occasionally update it. In the meantime, I will probably post my Aun'shi deck online soon as well, since I've been trying to run him, as he is the newest warlord. So expect that soon.