I honestly feel that for a band to have a spectacular performance, they must have a slow movement. Does that mean that they have to march slow, of course not. It just simply means that they can be playing at 80 BPM but march in double time at 160 BPM.
For example, look at the top 3 placements at the 5A State Finals last year. Duncanville with October, Cedar Park with the ballad in Jupiter (one of my all time favorites), and L.D. Bell with Blue Cathedral (i think).
For any band to truly move and inspire the audience and judges, you have to have a part of your show devoted to the emotional side of music playing.