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Farseer (runes of Witnessing, runes of warding, Spirit stones, singing spear, doom, eldritch storm, fortune. guide) 198
7 pathfinder rangers 168
16 guardians (eldar missile launcher) 148
16 guardians (starcannon) 153
4 dark reapers, 1 dark reaper exarch w/tempest launcher, crack shot, fast shot 237
All in all i think if you replace the guardians with Dire Avengers and bring down the cost of your farseer your list would rock. You could use your pathfinders to distract, and pin your opponent while you run the Dire Avengers up the field to put more preasure on and to release the mighty sword wind! This leaves your farseer back holding fort and guiding the reapers dealing death from afar. Alternately if your enemy has no armoured vehicles or little, you can attach the farseer to a DA squad and guide them to victory and doom your opponent to their death.
Ultimately no one can tell you how to run your army, I just offer my opinion to you to glean what you will from it.
~May you not stray from your path, Gaius.
the pathfinders look fine.
With the guardians, you've got a big squad which is good but since these are most of your troops you might want to increase their chances of survival by adding a warlock to each. maybe a scatter laser would be better because of their low BS.
the reapers look good but you only really need one of the exarch powers.
overall it's not a bad list but lacks Anti tank with only the EML and spear for heavy tanks and the reapers and starcannon for light tanks. you will probably have trouble taking out some transports.
I'm mostly just using the guardians for damage soak right now, and they do well. I'll definetely look into using dire avengers though! As for my farseer, to be honest, I'm mostly just trying to make up for my lack of eldar models at this point, so he's definetely coming down in points soon. After a friendly game with some guardsmen, I did in fact realize that I lacked a reliable anti-tank unit, so I bought a wraithlord to get in some heavier damage against vehicles. I also grabbed some super cheap warp spiders because they look really neat.
if you do want a farseer that does everything, Eldrads only 12 points more, toughness4 so plasma doesnt instant kill, 3 up invuln and ignores armour saves...plus the chance of 3 powers per turn, knows all powers, and can mess up the oponents deployment completley.
in 1000 pts you could take another unit of reapers or pathfinders and drop guardians with starcannon, move his units to his table edge or back corner and take them apart as they march towards you (you can buy at least 1 extra turn of shooting with this)
perhaps drop fast chot and just stick with crack shot as you cant use both at the same time.
perhaps a wraithlord or 2 war walkers with EML if you can get them in, or vypers to harrass them.