Your list has been selected for inclusion in the Big List of Eldar Lists project! You will be receiving a score from me using the 5/5 system as outlined in the Big List of Eldar Lists in the stickies on this board. In your case, check further down - your entry has been added to my post so I can see if my table structure is working properly [and so that I don't look too lazy]. Following is the critique I have given:
Background: .5
Wow, the fluff is interesting though unfortunately short. This is Eldar from a slightly less noble and fairly original angle for me. It's good that you mention it is for a tournament, and that it's meant to handle anybody, but when a tournament list is built for a specific list it is good to know the particulars of the event [even if a simple link is used]. At such an event it is not just how you play, but also in some cases painting, sportsmanship, composition, and extra objectives or special scenarios that will determine how "good" your list is. Since your list will ultimately be judged through the lens of this event's coordinators, it would be good to have some sense of what the event demands of you.
Composition: .5
Your troops choices are hovering at the minimum and are duplicates, though paired avenger teams do make sense they are one of the least versatile units in the codex and need support. You have a nice assault unit but at the 1500 level two squads capable of assault would be much better, in case they get stuck on one side of the board while your enemy encroaches on your shooting line. You have a wide variety of shooting units good at handling a large number of targets and supported with some nice synergy through your farseer and varied unit types, so this will really be your phase. It is too bad so many points have been eaten up by your heavy support section. The list holds to your fluff pretty well [at least so far as what's been presented], but I'd like to see how the list relates to the tournament requirements. Composing an army list is much like composing music or art; you need to consider the demands of your audience [in this case the organizers and judges] and be able to justify your decisions.
Utility: 0
The first thing I look for in a list when I see a farseer with guide is warwalkers. You have them; excellent. Next thing is doom. You have 2xAvengers and some banshees, as well as hawks - all of them need this. Next we look at Mindwar. With a Farseer who has two powers that greatly enhance your list without requiring that he make himself vulnerable, why would you ever want him to have LOS to an enemy? On top of that you will want to use your other two powers every turn, meaning you will not want to use mindwar instead. This is points wasted. Runes of Witnessing I am not sold on either as they improve the odds of your farseer suffering from head-explodey.
Banshees jumping out of a Wave Serpent should always be doing so to charge the enemy. Acrobat is not really necessary, and Warshout is more useful when multiple squads are attacking the same opponent [as a banshee's warshout benefits all of your allies who are assaulting the same squad as the banshees]. Mirrorswords are okay but for a squad that wants to kill things in combat, the extra strength of an executioner actually tends to give you more victims in more situations, meaning mirrorswords tend to underperform. The extra banshees you could get instead of buying an Exarch and Mirrorswords add far more attacks if that's what you want. The scatterlasers on their serpent are an unnecessity as the vehicle will almost always be in enemy lines within arm's reach of the enemy; if you want more shots the dual shuriken cannon costs less and has better AP.
The Avengers are designed with shooting in mind. The Exarch adds to this. No wasted points there.
With doom in your list the Sunrifle is actually a pretty fair weapon for the hawks. Intercept is not necessary but inexpensive and nice to have, and adds a lot to the squad in the right situations.
The Double Prisms make up for a lot of the resilience your army is lacking and add some high-powered ranged punch, and in the open will force the enemy to think carefully about gunning for them or the Walkers. I'm still not sold on holofields for fireprisms. The walkers themselves have quite some points sunk into them; be sure to make every one of their shots count. I'm also not sold on spirit stones for walkers, though these cost far less and can help the walkers to flee from bad situations if they are deployed in cover.
If you lost mindwar, runes of witnessing, acrobatic, warshout, both holofields on the prisms, and swapped the scatter laser for two shuriken cannons on the serpent, you would end up with an extra 115pts - almost a third fire prism, or an extra troops choice of some kind. You could trim a little more fat [9 man avenger teams, for instance] and come out at 139 extra points. too many upgrades may also hurt your tournament comp score due to a lack of troops choices which can be bad for your overall performance. More thought needs to go into this area, or justification for these upgrades needs to be provided.
Flexibility: .5
The main issue in this section is your Banshees and Avengers; together they are about 1/3 of your list and both of these units will struggle with a number of enemies due to the low strength of their attacks. There are a wide variety of enemies that neither of these units will be able to handle. Other portions of your list make up for this, but an opponent who is canny and able will eliminate the units capable of coping with his army and face the remainder at a marked advantage. So you will need to plan against this eventuality. Your other units are generally capable of handling most enemy targets, with some measures included for the rarer high-armor vehicles. Not bad, but could be improved.
Ingenuity: 0
No mention has been made of the general strategies you will employ, how you will relate your approach to the conditions of winning the tournament, or any of the combos that are available for this list. Additionally you neglect to consider your vulnerabilities and how you will safeguard against them. Without some sort of a plan to guide this army to victory all battles become much more difficult, especially because there are a number of units in this force that must still pull their weight in situations that are not ideal. As an example I recently played a game with 2 Defender squads and 2 Avenger squads as follows:
128: 8 Avengers, Dual catapult exarch with defend
128: 8 Avengers, Dual catapult exarch with defend
140: 10 Guardians [1 EML] + 1 Warlock [embolden]
140: 10 Guardians [1 EML] + 1 Warlock [embolden]
My opponent had 6 Killa Kans and a load of Nob Bikers with FNP and a 4+ cover save, as well as two warbosses. My Avengers got mowed down really quickly, because their guns are horribly inefficient at killing bikes [even when doomed] that have multiple wounds and are essentially fortuned.
My Defenders ultimately got owned too, but they managed to down 2 kans as they crossed the table as well as killing a Warboss in Close Combat [mostly due to volume of shots]. Since the Avengers had nothing they contribute I used them as a speed bump, allowing the Defenders to advance and clear out some of the impending threat. If you face an opponent with 9 kans and 2 dreds [not likely but it is 2 troops and 3 heavy support, so quite possible, and comes in at under 700pts], how do you intend to use your banshees and avengers? Things like this need to be considered.
Total Score: 1.5
You have been graded somewhat harshly because this list is for a specific event for which there is no information provided, and also because more explanation for your choices and how you intend to use them together needs to be included. Without justification, some of your selections seem inefficient considering the points invested. Additionally, considering standard tournament comp scoring, your list is likely to not earn free points that would otherwise be available. While a tourney that lacks comp scoring would make this a nonissue, it is necessary for the purposes of review for such information to be included. This list would be difficult for another player to have to use in a tournament if they had to rely entirely on your explanation of how it functions.
You do get bonus points for some interesting background material about your craftworld.