A number of people have commented in the past about the lack of live clean vocals and I agree it is a bit disappointing to not have them performed.
I definitely think they could incorporate some stronger effects into their live show to compliment the performance. Imagine something along the lines of Dimmu Borgir caliber lights and smoke - would make it a much different performance.
04/05 - Kataklysm, Aborted
04/08 - Carcass, Gorguts, TBDM
04/23 - Behemoth
04/24 - Nile