Hi Turnerm, I think, whilst your ideas may still seem messy or "vague" as you say, what they will look for is a strong proposal with the potential to lead to interesting and new research, i.e an open study which does not go from A to B simplistically, but has room to stop at XYZ in between. You don't need to know, step by step, how and where and when your PhD will happen, but you will be expected to have a definite direction, questions you want to address, areas of study you plan to research, a proposed timeline of sorts that shows you understand the scope of the study rather than a definite plan of action, and notes about current and exisiting studies that you want to examine/answer/expand. Your reasons for raising these questions, and the areas you hope/plan that your ideas about current studies will lead to, should make for a lively discussion/debate. :)