That's their strength, but they can't kill for ****. I'd advocate a +2 or +3 to attack melee across the board for all Chaos infantry! And maybe a +5 to all melee strength....
*slams counter* Like dammit they are CHAOS!
*slams counter harder* They are heavy metal vikings!
*slams head on counter and bites his shield* For Khorne!!!!
"Burn! Burn with the fires of Change! Scream your hymns to Tzeentch!"
-Tal'gatha the Fallen