Here are some quick thoughts on the state of Craftworld Eldar HQ units now that their prices and rules have been adjusted in the new FAQ.
Phoenix Lords & The Avatar of Khaine - the relative strength of these remains what it was before the FAQ. Baharroth and Karandras are a bit weaker due to both them and the Aspect Warriors they support taking a hit due to the new beta reserves rules. Illic and Yriel are about where they were as well.
Autarch Variants - No major changes here. The Swooping Hawk Wings Autarch is a bit worse under the new beta reserves rules, but it wasn't too uncommon to bring him down within your own lines anyways.
The main attraction here is the changes to our psykers, though, particularly the points costs for Farseer and Warlock. What does that do for us?
Eldrad Ulthran - Now that the Farseer is more expensive, Eldrad is, relatively speaking, a better deal. He's about 50% more durable than a Farseer and 50% more capable at spellcasting, not counting his bonuses to cast. Eldrad used to be just about 50% more expensive than a Farseer, making him a reasonable choice. Now he is only 35% more expensive than a Farseer, making him a must-take in any Ulthwé Army.
Farseer - The price increase is minor compared to the huge utility this unit provides. The Farseer remains an excellent choice in every Eldar Army. I will continue to run one.
Farseer Skyrunner - Due to the Farseer price increase, the gap between Farseer and Farseer skyrunner is smaller. For a mere 23% increase in price over the base Farseer, you are getting plenty of shuriken shots, higher toughness, and great mobility. I find that the solid base mobility of the Farseer to be good enough for my purposes, but this is now a much more reasonable choice.
Warlock - The significant price increase to the foot Warlock means you are now paying typical-HQ prices for what is very much a not-a-typical-HQ-durability model. This guy dies to 6 snipers shooting at him on average. Back when he was very cheap, this wasn't a problem. Nowadays, unless you absolutely cannot spare the points, you should upgrade him to a Warlock Skyrunner or Spiritseer. I won't be running this HQ any more.
Spiritseer - We all knew the points nerf was coming for this model. Interestingly, as the Warlock has also taken an equal-sized nerf, the Spiritseer remains a solid HQ choice. You may not care for the Spirit Mark or the better Smite, but for a small 18% price increase (down from 28%), taking a Spiritseer instead of a Warlock means you won't lose your HQ to your first perils, which matters a lot more now that we're north of 50 points per model. I will replace a Warlock or two with a Spiritseer.
Warlock Skyrunner - As it hasn't faced a price increase, the Warlock Skyrunner is only a little more expensive than a foot Warlock. The extra toughness and wound make it comparable to a spiritseer, but it can still die to its first Perils. Since the upgrade is so cheap, it's much more worth it, particularly since 1/3 of the cost of the upgrade is the guns that come on the jetbike. I'll take one of these.
Warlock Conclave - This was our worst HQ unit before the FAQ, and I think it still is, even if the discount compared to base Warlock price is greater than it used to be. Lacking the Character keyword and being generally expensive for its level of durability, this unit should only be taken if you have a particular need to use Concordance of Power for something.
Warlock Skyrunner Conclave - No changes here, though relatively cheaper compared to Warlock Conclave.
Side Note: The Hemlock Wraithfighter is now, relatively speaking, stronger than it used to be. If you consider "ability to cast Jinx on a particular enemy" to be part of its package, for example, the relative difficulty of getting this from elsewhere in the army has gone up. To demonstrate, imagine if every Runes of Battle caster cost at least 140 points. This would make the Hemlock the best source of Jinx. The Hemlock isn't stronger than it used to be, but other units that do the same thing are weaker (for their cost) and so it should be considered more seriously.
I used to previously run a detachment like this:
Pre-FAQ Battalion - 2 Warlocks, 3 units of 5 Rangers - 250
I found it to be inexpensive and capable of adding a lot of flexibility to my army. Even if the Warlocks underperformed, or died to Perils, or were redundant with other Runes of Battle casters from my other Battalion, it wasn't a major issue because they were so cheap. If I were to run this detachment today, the Warlocks would be 39% of its cost rather than 28% of its cost. It is more difficult for them to earn their points back by supporting units, and every one lost to Perils or a few snipers is a big punch to the gut.
Warlocks are now a significantly bigger tax. This is particularly the case when you bear in mind that a Farseer costs about the price of 2 Warlocks, and has similar casting abilities. Is that Protect really better than a Fortune? Is that Jinx better than an Executioner or a Guide? If it weren't for the fact that 2 Warlocks take up 2 HQ slots and 1 Farseer takes up only 1, a lot of times there would be a case to be made for taking a second Farseer over a pair of Warlocks, particularly given how vulnerable Warlocks are to Perils.
The best choice, in my view, is to try to mitigate the downsides of Warlock. If our Psyker that can cast Runes of Battle is going to be expensive, we should invest the points to protect them from Perils and easy sniping.
The Spiritseer is in my view the obvious choice over the Warlock, now, even if you don't intend to smite. The Warlock Skyrunner is only marginally more expensive, and though he can still die to perils, it's less likely, and he comes with good dakka and maneuverability.
Some new Battalion layouts I am considering:
Battalion - 2 Spiritseers, 3 units of 5 Rangers - 310
Battalion - 1 Spiritseer, 1 Warlock Skyrunner, 3 units of 5 Rangers - 315
I am also considerering dropping my second Battalion. Now that Battalions grant almost twice as many CP, and Eldar's cheap HQs are much less cheap, Swapping from Battalion+Battalion+Vanguard to Battalion+Vanguard seems like a natural choice.
Bat+Bat+Van under the old system yielded 10 CP, and leaving out the Farseer leading the Van, required 4 Warlocks costing 140 pts total
Bat+Van under the new system yields 9 CP, and leaving out the Farseer leading the van, can be run with 2 Spiritseers which is cheap enough to make up for the increased Farseer price.
This way, although I lose access to a couple spellcasts per turn, I can leave the rest of my army mostly untouched and keep roughly the same CP.
How about you? What are your plans for Eldar HQs now, in the shadow of the big FAQ? Has anyone found a good use for the new Warlock?