I can't really imagine any dates filling up (except maybe the first week) unless Disney set the limit is really low and NO ONE who had a reservation on a particular day (say 12/25, for example) cancelled.
I would gather there will be still plenty of availability come June 28th for the "have tickets, but no resort" people (especially since AP holders are limited).
I just don't know what I will do (being a person who has tickets, but no resort reservation anymore). Do I just make some park reservations and hope I can eventually get some resort reservations to match in the late fall, early winter?
I have the problem of that ONE of my families ticket is an unactivated AP, but the rest of my family tickets are 5-day. So .. I won't be able to reserve parks for 5-days for the entire family (not that it matters .. since I don't know when/if I can resort reservations).
What a weird, backwards system .. but gotta start somewhere I guess.