We don't worry about it being slow at the resorts so much as it being slow at the parks. If you are asking which times are easiest to book on short notice, I would say February and September fall in that catagory. DVC resorts attempt to have full occupancy at all times, so it's a bit of a relative thing.
That is what the "seasons" try to do. Make it more attractive to come for longer periods during "slow times" and less attractive when it's not hard to get people to come.
I like to go towards the end of September. Not to crowded in the parks and it has started to cool off by then! We made a ressie at BWV for a one bedroom at the 7 month mark with no problem
No, but the points are arranged throughout the year to normalize usage. The idea is to have the resorts at capacity at all the time with the exception of about 4% for breakage and rehabing units. That's why rehabing is a slow process and is often an ongoing thing over the entire year.