Take more units, not bigger ones. Brazen Fury triggers per unit that loses a model, not per model lost. Three medium possessed units that each lose a model surge three times; one large unit that loses three models surges once. This is the single most important list-building consequence of the pairing.
Let them shoot you. The instinct to hide is wrong here. Every enemy shooting unit that kills a model in a possessed unit hands you free movement in your opponent's own turn. Present targets deliberately and take the advance.
Hold Archslaughterer for the decisive turn. At 30 points, Archslaughterer turns on every Blessing of Khorne at once for one unit until the start of your next turn, once per battle per army. Put it on a cheap character attached to your best possessed unit, and use it on the turn that decides the game rather than the turn that feels dramatic.
Use Warp Stalkers to beat screens. Rewritten in this pack, it lets your unit move through enemy models excluding MONSTERS and VEHICLES, and crucially it can end a Charge move engaged with what was behind the screen. That is the answer when your opponent puts a cheap unit in front of the target you want.
Punish the Craven stops the walk-away. In your opponent's Movement phase it forces an enemy engaged with your character to use desperate escape mode when falling back. Neutralising a melee character by walking away from it is the standard counter-play, and this shuts it down.