my $.02... a show doesnt NEED a slow movement. variation of tempos, if done correctly, can add alot to a show, but it isnt neccesary to have a good show. Alot of shows would be better without their ballad. The ballad only helps if its done correctly, and many bands look at the ballad as the breather, the break, etc. but truth is, it is probably the hardest part of your show. It deserves alot more attention than it gets. A ballad done well shows the maturity of a band, not only can the band play loud and march fast, but they can make music. The ballad is normally my favorite part of shows.