ouch 2006 points...can't use that anywhere, try and to trim off the fat so to speak
Well unless those Guardians are storm guardians they must have a support platform and since you have plenty of anti-tank I would recommend scatter lasers or the cheap shuriken cannon but if you have the points Eldar missile launchers are the best choice
The striking scorpions exarch should have an exarch weapon which one is just prefrance (highly recommend: chainsabres :P)
If they are storm guardians then giving them a warlock with enhance is almost a must (conceal is a good option if you have the points) because it makes them pretty deadly assault units for standard troops they should be able to hold their own against anyone and if you throw in two flamers they can take out squads of slugga boyz and gaunts (if you make it one full squad of 20 or have both squads shoot and charge)
The wave serpent is transporting the dire avengers yes? thats good.
Why a banshee mask on the autarch? mandiblasters are the better choice with his already high initiative
The falcon should have the holo-fields instead of the Prism because the falcon is transporting valuable troops and must get close and personal to the enemy while the Prism with it's 60" range can stay out of harms way
Nice list just a few tweaks and one legal issue