In my (admittedly limited) experience, the hexrifle is just not good. Yes it can attack enemy characters, but it's a heavy weapon and only deals 1 (maybe 2) damage. Wracks want to be mobile, so you're only hitting on 4+, wounding on (probably) 4+, and most targets will have good armor or an invuln so even the ap-1 isn't amazing. At one shot per unit, it's just not good. The FAQ'd Stinger Pistol is a much more reliable option.
Haywire blasters are bad. They're relatively expensive and less reliable than they used to be, and now that everything has 10+ wounds even throwing a suicide squad at a tank means you might manage to slow it down. If you want a shooty Talos, either the stock double splinter cannon tail or the stinger pod (so you can advance and shoot) works pretty well.
Also it looks like you're missing a Raider? Or something, 2 of the Wrack squads are going to have to footslog and you know how the Dark Eldar feel about getting dirt on their boots.