The two times I have done the wait list for BWV, Reservations came up with something. The first year, I reserved at OKW for 11 nights in early August and MS came up with half my stay at BWV (I didn't want to move during my vacation, so I declined). However, just today, exactly 30 days before my arrival date, they came through with 12 consecutive nights at BWV. I had reserved at VWL and actually had a tough time deciding whether to keep VWL or go to BWV (I chose the latter). I think I made the right choice, but I'll know in 30 days.
So I guess what I'm saying is hang in there, I think you will see some more cancellations and you still have a chance.