To help answer a few questions about admissions to SU, I'll try to help.
1) Our Admissions Coordinator is out on a medical leave, so that may be the reason for the delay in responses. There was a temporary replacement for her announced in an email about a week ago, so hopefully things will move a little faster for now.
2) Our class sizes are a lot smaller than 300. This year, we have 69 students at our main campus, in Winchester, 4 at our Ashburn campus, and about 5 GW students who are 3rd juniors that are either admitted for next year or waiting for a decision (they are also at Ashburn). All of the professors know my name, and then names of most of, if not all of, the other students in our class.
3) Deferred admission means that if you are admitted, you can defer your entrance for a year under certain circumstances. One of my classmates did that, but it apparently does not happen very often. I do not know what circumstances they accept, but if you need to take a year off before you start for personal and/or health reasons and you have a strong file, then you may be granted deferred admission.
However, if you get accepted and want to wait and see what your chances are with other schools, then you need to decide how much your non-refundable deposit is worth to you. "A bird in the hand is better than one in the bush." I was blessed and accepted the first year I applied for pharmacy school, but I have classmates and friends at other schools (VCU, Howard, Temple) who applied to pharmacy school for 5 years, every year, consistantly working to improve their PCAT scores, taking add'l classes, etc before they got in. So it's up to you how much you want a spot in the class of 2013, and how much you want to get into your "ideal" school.
Hope this helps!