What you want to do is focus on the positive. If a client asks me to write two emails but I see there is more that they need to do because they are missing out on opportunities, I don’t generally mention that in the initial interview. I always try to go from a known to a known to an unknown. As you work on the project you can mention to them that you are seeing an opportunity that will help them. For example, you might say: “I’m deep into the research of these emails and I’m seeing that there is more that we can do here. There are 5 major benefits. We can focus on one benefit in each email.” I just shifted from a simple email campaign and added more projects. They understand email and may be more willing to add them.