So, the transfer to 6th edition. The main item here is obviously the Venom. The damage they can do with double cannons is somewhat improved against less durable foes who suffer from the cover reduction but against more durable foes - no real changes. Venoms are still anti-infantry only platforms which put out a bunch of wounds against any target. Hull Points have made vehicles across the board less durable - firepower is more reliable against them despite a very forgiving vehicle damage table. Dark Eldar vehicles were generally quite reliable to drop previously so this isn't a huge change - on average Venoms still die to two penetrating hits and now die to two glancing hits (compared to three-four previously). The 5++ from the flickerfield is less useful as Venoms now come with Jink - as long as they move they get a 5+ anyway though at least the flickerfield works in combat and when the Venom doesn't move.
So...it's basically more Dark Eldar-y than before. More firepower, against some targets, and more fragile than before. The main weakness here is your basic gun can drop Venoms without too much difficulty and with the changes to Rapid Fire weapons make this more possible at range. This means overall Venoms got a little weaker though Nightshields and pre-measuring can mitigate this early turns. This means the basis of how the army works has to change a little - the early alpha-strike with Blaster Warriors isn't really going to work as pushing Venoms in doubletap range of S4 weapons is going to see them dropping quickly.
This means getting more ranged anti-tank elsewhere in the army and with Allies (i.e. Eldar) we have a few more options here. Anyway, let's see what we can do...
2x3x Trueborn w/3x Blasters, Venom w/Night Shields, 2nd Cannon
4x5x Wracks w/Venom w/Night Shields, 2nd Cannon
2x5x Wracks w/Raider
Farseer w/Runes of Warding, Doom
2x10x Storm Guardians w/2x Fusion Guns, Wave Serpent w/Scatter Lasers
We've got the same core as before Venoms + Raiders/Ravagers though we've dropped the Warriors for Wracks for a more durable scoring platform. Eldar add some extra scoring since Dark Eldar Troops are likely to see more time on foot (i.e. dead) but aren't really making up for the loss of anti-tank lost from the blasters. Ranged S6 is nice and Doom makes all that posion very scary but it's not cheap and more durability based compared to firepower based.
All in all...not great. It's okay and I'm sure with further playing there are some refinements which could be done but the core really got weaker and Allies aren't really shoring it up unfortunately. You could always try a double FoC Venomspam spectacular with just min-sized Troops in Venoms + Ravagers/Razorwings to crack things open but that's really one-dimensional with limited vehicle cracking ability (all stuffed into one grouping of vehicles).
In the end, I think pushing in the direction of a less spam approach and using Venoms to support the rest of the army is more likely what will see success for Dark Eldar.