Either increase the 8 man difficulty - 10 guilds cleared it in under 3 days,
or decrease the 16 man difficulty - 2 clears of Tanks and no clears of Kephess.
Personally, I'd suggest increasing the 8 man difficulty, I'm 1/4 NiM EC and thought that NiM Zorn & Toth were a letdown
Is NiM EC Kephess a step up from the Drouk Brothers? Someone in Astral described him as being very well tuned on 8 man. I'm curious if anyone with 4/4 agrees.