no, all applicants have not been contacted yet...
no one can predict what will happen this year regarding the wait list... the recent trend in more accepted students deciding to matriculate could be due to any number of reasons; The new P/F genes to society curriculum, the new state of the art medical teaching building, the new 600+ bed state of the art hospital that will open next year are all recent changes that may be playing a role in less students deciding to go elsewhere.
In addition to the recent changes, we also asked students that were accepted but chose to matriculate elsewhere what they did and did not like about Hopkins in a very detailed survey. By listening to applicants, we are constantly trying to improve as an institution and continue to make ourselves more attractive to candidates! So I think its a combination of all of the above that has led to the decreased pull from the wait list.