Speaking of the shrieker cannon it now has two fire modes. The first is identical to a shuriken cannon whilst the second is a single 2+ poisoned shot that had the potential to cause further wounds. Unless the enemy unit is particularly bunched together you're probably going to go for the normal shuriken cannon option but the shrieker version could be great against cheap units like guardsmen. Having Precision shots is great for sniping models too.
Finally, the Death is Not Enough rule is what is really exciting. You only have to cause a single casualty to force a morale check at -2 leadership. It's not clear if this modifier is cumulative with other effects but the Mask of Secrets is tempting as it would make Ld10 into Ld6 if they do stack. Let's not forget the Armour of Misery in the DE book too for a further -2 to Ld. That would mean anything Ld8 would flee on anything but a snake eyes. Not only that but you choose the direction of the first fall back move. Obviously this is situational but if you're on your own table edge it would be fun to make an enemy unit flee the board! Bear in mind that the Mask can only be taken by a Shadowseer though so you'd need one in the same unit or nearby.
That comparison is perhaps unfair though because the main reason you need a Shadowseer is for the excellent Phanstasmancy (bit of a mouthful) discipline. The main reason for this is that the old Veil of Tears power is the Primaris. That power alone makes up for the frailty of the other units and justifies the cost of the Shadowseer. Although remember this doesn't work from a transport unfortunately. Since you've got seven Elites slots I don't think it's unreasonable to take 3 or more Shadowseers so that each of your Troupes (and possibly an allied unit) has the benefit of the Veil. Let's take a look at the rest of the powers too:
Dance of Shadows - combine this with Veil and a unit could be incredibly durable. Nothing to stop you using it to boost a nearby vehicle's Jink save either.
Peal of Discord - reasonably effective Nova power but the main bonus is Concussive which helps reduce the initiative of an MC or similar before combat. Of course that's assuming it matters since your Harlies are I6+.
Shards of Light - Blind can be useful at times and there's the potential to seriously deplete a GEQ unit.
Fog of Dreams - sort of an inverse Invisibility. Difficult to say which is better. Invisibility makes one unit very durable but doesn't stop your enemy shooting something else. WC2 though which could be tricky if you roll low on your warp charge generation.
Laugh of Sorrows - potentially extremely devastating particularly for single model units and works on Fearless units too.
Mirror of Minds - kind of a buffed Mind War but with potentially limited warp charge it might be tough to make it Focussed.
You're going to want to cast Veil with all of your seers a lot of the time though so I think ML2 is a necessary upgrade if you want to cast anything else with any of them. With access to Telepathy I think the best option is to simply take the primaris from each giving you Veil and Psychic Shriek. That's a pretty awesome combo and without many warp charge dice it will mean your seers are likely to be able to cast two powers each as both are WC1. Of course Psy Shriek is best on the Seer with the Mask since he'll reduce enemy Ld by 2. So you could happily roll on Phantasmancy for your other Seers but having several Psy Shrieks can be devastating. Don't forget that two Seers in the same unit can't both cast it though.
Let's look at the Shadowseer himself some more though. His grenade launcher is fairly pointless against most targets. It can't hurt anything above T4 and at best will cause a couple of wounds. Interesting that the Pinning test is automatic rather than needing to wound though. The staff on the other hand is much better as it will be S6 on the charge giving him a chance of damaging some vehicles although wasted against anything else since it's Fleshbane. Concussive is again of debatable use since your army is likely striking first anyway. I'd consider a neuro disruptor to give him a bit of punch on the way into combat but again if you're running to get there it's a waste. I'd say keep him cheaper as you'll want more than one.
As I've mentioned, that statline makes him a bit of an animal in close combat. The combination of
I'd personally never make him my Warlord as although he's probably the easiest to keep safe you'd be wasting him and losing the opportunity for an excellent Warlord Trait. They may as well have just said he can't be your Warlord.
Finally, his Blitz move has potential to be a game winner. Assuming you use it on turn 5 you'd move an average of around 18"and still run and charge. Potentially he could move a huge distance but I wouldn't rely on it as he might end up moving less than he normally could. Still, the big thing is having 10 attacks (well 12 on the charge). That's enough to wipe out an enemy unit if he's even a little bit lucky.
If I wasn't excited about this book before, the Elites section has certainly got my mind racing. All three of the characters here have something to offer. The Death Jester is probably the weakest of the three but he could still be awesome with his Death Is Not Enough ability. Shadowseers are practically essential for the army and I use the plural deliberately. I can imagine the Solitaire being incredibly good but equally he could get shot down before doing anything at all. Even with EW he's still just 3 T3 wounds so he won't last long in the open. He just seems too much fun not to take though, if nothing else just for the look on your opponent's face when you explain his statline and rules.
It's funny really that the only optional bits of the book are the most exciting. As I say though, they've got my mind racing with the possibilities when combined with my Dark Eldar though. I really didn't want to buy any more models for a while but I might struggle to resist next time I'm at my FLGS.
Anyway, deep breath. The next post will be the last of this review where I'll talk about the formations in the book.