I have been a business writer for some time now. Most of my thoughts on writing have been influenced by "On Writing Well" by William Zinsser. The crux of his work is, simplify, simplify, simplify. You don't need big words. You don't need to sound big. You just have to convey the message in as few words as possible. When you do that, do you need a big vocab? Seems useless to me. What do you think?