I like this idea. I would say, though, that it teaches "how to make a specific statement", rather than "noticing WHEN you need to be more specific." If you're running in to groups that have trouble understanding what a specific statement is, or coming up with their own, this would be a very useful precursor exercise, though.

It's funny to realize that telling the entrepreneur to "be more specific" doesn't work, because you weren't specific about what "specific" means! :)