I am sure ED would make the life of adcom a lot easier at UMich. The unpredictable yield rate either lead to over enrollment or need to use the wait-list more. It is very hard to be right on target like this year. The question is how many students they will admit from ED. Obviously, that would depend on the number and quality of ED applicants. If only fill a small fraction of the upcoming freshmen class with ED, it may not help the situation much though.