So here's the list I'm working on for next year. It leverages two Dark Eldar formations: the Kabalite Raiding Party and the Haemonculi scalpel formation. I like it quite a bit cause it puts a fair number of models on the table and it's super shooty. Everything can deep strike. Everything is fast fast fast. And there's lots of guns.
Granted, for purge the alien it'll be rubbish but with all of the small squads that sport some pretty slick weapons that can take on both infantry (very well) and vehicles (fairly well). I'm also kinda sad that I can't fit in a Void Raven, a Razorwing or a couple more Ravagers. The good news is that I can still fit all this stuff into the DE equivalent of the combined arms detatchment.
Dark Eldar will always be rubbish in kill point missions. Could you drop the hellions for another ravager? Also I'm not sure about the wrack formation: I feel like you could replace them with a stronger assault unit (though I don't recall what the formation does, so it might be worth it).
In in my league game against DE, reavers were used to great effect. I recommend trying them with the new codex.
Am still worried about your anti tank arms. Agansit infantry and hordes list I think this would be a solid list but am just noticing less anti tank then what you ussualy run just curious what your ideas to engage agansit knight or other heavy armour threats?
The formation I chose, "Kabalite Raiding" party gives me an additional command benefit: Architect of Agony. The bonus is the Power from Pain is treated as one turn higher. Neat. The draw back? Hellion Tax. The force organization is pretty well fixed at 1 Archon. 1 Court. 1 Incubi. 1 Ravager. 6 Kabalite Warriors. 1 Scourge. 1 Hellion. All of 'em have to be in transports if they can be. So that's the restriction to grab the Architect of Agony. I could also use this list as a base for the "Real Space Raiders Detachment" if I want more flexibility.
Yeah, the anti-tank isn't great. I might rearrange some of the special weapons to ensure the maximum number of blasters and dark lances.
Lastly, the Wrack formation: Grants d3 victory points on First Blood and can deep strike on turn one. They're there to remove any rear action things like devastators, thunderfire guns, snipers, etc.