Here is the build I have been using on Normal with a full group.
So far everything just wastes away before my teammates get to the mobs. The only person who catches up to me is the barb that has to leap into a group to get any dps in. I absolutely love Locust swarm on lager mobs since it will just jump from pack to pack to pack front loading my damage done.
The only thing I actually "spam" is acid cloud but mostly as just to blanket an area in poison, locust swarm I don't spam, I only keep it active.