The most important suggestion: never take Wracks as Elites. Grab a Haemonculus so they act as Troops. Bump one of the Wych squads to eight models and put them in a Raider, and have the Haemonculus ride with them. I'd make the other Wych squad bigger and put them in a Raider too. The foot Warrior squad needs a raider too. Pick up a largeish hellion unit and have the Baron use his PT trick with them. Or, if you don't want hellions, skip the token swap and put him with beastmasters.
"Let the vermin burn. We shall drink deep of their screams this night." Archon Farath Müre, High Archon of the Kabal of the Consuming Flame
(11/5/2013: A few things have been added to the Kabal's fluff, most notably shifting their base of operations into the Webway, sort of, and adding an alliance with the Alpha Legion, or at least a few heads of the hydra.)