A friend of mine recently took a tour of the Craftworld so to speak when he started assembling an Eldar force of his own. One of our early discussions was over which is better, a Farseer or an Autarch. His position was that the martial prowess of the Autarch was superior to the psychic wizardry of a Farseer. I accused him of thinking like a mon keigh (okay I said Space Marine, but I don’t want to estrange any Space Marine players out there.) Indeed, it was true that when I began playing Eldar I consider the Farseer to be nothing more than a wizard, sitting back and casting spells. I was befuddled on how to effectively use this HQ unit in my army and often ran a stripped down Farseer just to fill the Force Org. Slot. It wasn’t until, after a two year sabbatical from the game and the 4th Edition Eldar codex was released, that I truly began to walk the Path of the Seer.
Like the codex itself, running a Farseer takes skill. At its core you have a potent support unit. The ability to re-roll almost every major die roll in the game can not be overlooked. Certainly with codex creep and a clear push by the powers that be to enhance psychic powers within 5th edition the Eldar have competition, but still no other army holds a candle to the reliability and utility that a Farseer brings to the table.
We are all familiar with what Doom and Guide can do for a Dire Avenger Bladestorm (If you are not familiar, try it, it’s pretty awesome) but consider using other psychic power combinations on other units. Consider what fortune and doom used to augment a Howling Banshee assault might do to your opponent. Fortune and guide your Fire Dragons before they go after that Land Raider and make sure it is destroyed.
You should be casting two psychic powers per Farseer per turn (and a third from Eldrad if he’s on the table) There is nothing to be afraid of. With Runes of Witnessing, Ghosthelms and the potential for a Warlock with the embolden power you really don’t need to be concerned with perils of the warp or even failing a psychic test for that matter. The only anti-psyker wargear that causes me to think about casting a psychic power is the psychic hood and only turns into a roll-off between you and your opponent.
It’s for these reasons, the overall army enhancement and the reliability of such enhancement that I use Farseers over Autarchs.