But the Autarch gets more than just the Exarch stats, they get a MW, and have both FF and CC Extra attacks. Costing 75 points might even be on the *cheap* side.

Also note that the "high" cost of the Wraithseer takes into account the fact that you're adding a supreme commander to a fearless unit, something that not many armies can do; point costs aren't based *just* on the stats of the unit, but on other "soft" factors as well.

Orks - Warboss in Great Gargant
Steel Legion - Commisar attached to supreme commander
Black Legion - Demon Prince
AMTL - Legate in a Warlord Titan
LatD - Also Demon Prince
Tyranids - Dominatrix (I think)
Necrons - C'Tan

Barring variant lists I think it is just Marines and Tau that don't have the option of a Fearless Supreme Commander.

That said it is of course quite correct to state that the cost of a SC does and should vary depending on the army. As this is probably more relevent than other small differences such a fearless or MW attacks etc etc.

Commissar doesnt make an IG unit Fearless, does it? Its a case where the Fearless model gets dragged along with the rest of the unit...

I'd be interested in seeing some of your builds for Iyanden armies, to see how my ideas compare. Im still hunting for "my" craftworld. I thought Saim Hann was it, but is proving too fragile. Fast is good. Tons of tiny units easy to break, not so much

It certainly does.

Commisar makes a single stand Fearless, but not the entire formation. It will get dragged along with the rest of the formation if you don't want to leave him behind, but cannot be subject to hackdown hits, or casualties due to taking a BM while broken. It's a life saver.

As to builds, my current 3k list is:

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Spirit Warrior Warhost with Wraithseer and Wave Serpents - 750
Spirit Warrior Warhost with Wave Serpents - 650
Aspect Warrior Troupe (3 DA, 1 DR Exarch) with Wave Serpents - 300
Aspect Warrior Troupe (3 DA, 1 DR Exarch) with Wave Serpents - 300
Night Spinner Troupe - 175
Swords of Vaul Troupe (4 Falcons, 1 Firestorm) - 250
Rangers x4 - 100
War Walkers x5 - 175
Nightwing Squadron - 300

Aspect Troupes pair with Spirit Warhosts for double taps, while the SoV and Nightspinners prep with BMs. The Rangers and War Walkers Set up alternating so that the opponent must deal with two formations to remove the scout screen. Nightwings are mainly for CAP and whittling away at broken units.

I'm still working on a decent Webway based list, though the Spirit Warrior Warhost with attached Wraithlords assaulting out of a marching Storm Serpent looks tasty (mmm... 105cm engage range) plus you can take the Storm Serpents in pairs, and double tap... It's a huge investment in points though.

Well, "fast, with lots of easy to break formations", is pretty much the standard for any "high activation" army, regardless of race, but Eldar are actually quite good at it.

Any "big" Eldar formations are going to be expensive, that's the trade off.

All Eldar units are going to be fragile to an extent, that's just the nature of the army.