I think a producer should be like water, and whatever the shape of the glass is, he or she should fill that. If they need you to be the engineer guy--typically I have an engineer--I work at that stuff. If they need you to be a songwriting help guy, I work on that. If they need you to be a vocal melody guy, I work at that, etc. I kind of look at whatever a band needs out of me then I try to give it to them.