Kolent

Why people puts Inmense power to a WoKB?? I don't get it.

I'm about to improve my khorne mortal army (1000) to 2000 points for this second edition and i'm wandering what to buy, as i see, karanak and flesh hounds are a good option, anyways, what do you recommend me to improve it? I currently own: - 1 Mighty Lord - 2 SLaughterpriest -1 Bloodsecrator -1 Bloodstoker - 20 Bloodreavers - 15 BloodWarriors - 3 Mighty SkullCrushers - 10 Bloodletters - 1 Korgorath Thankyou!