If I'm remembering correctly, Berserker squads can go up to 20 guys, right? If so, I'd fuse a few squads together (still a multiple of 8!). It will add more bodies protecting your Champs and Icons. So you'd have 3 or so squads of 16 guys each (or more if you want to toss out the multiple of 8 thing). There will be less Icons and Power Fists, but you want to SURVIVE all the shooting, so it'll be worth it.
As to the Greater Daemon? Eh, all your champs he can posses have Power Fists (except 1) which can be depressing to lose, even if it's for a Greater Daemon. I'd drop him, honestly. Maybe replace him with a Daemon Prince of Khorne, or a Chaos Lord of Khorne with a Bloodfeeder (on a Juggernaut, even, for extra scary-ness!)
Honestly, it looks pretty fun. Especially all the potential screaming for physiological points!