I think definitely October, Novemember, December...
My take...
December: First two weeks and New Year's Eve are definitely call at 11 months. Most of the rest of the month is slower to fill up due to the higher points. Getting a room at 7 months is possible.
October and November are difficult only at BCV and BWV. Even then, I see plenty of people getting those two resorts at 7 months and/or via the waitlist.
...now beginning of January looks hard...
January depends a lot on where NYE falls on the calendar and the scheduling of the WDW Marathon. And since the marathon is a scheduled event, its impact on bookings is far from set in stone. The dates are always subject to change and the event's popularity will vary over the years.
...April, and some summer months, especially around the holidays.
Do you have any evidence to support this? Sorry, but I have yet to see reports of people getting shut-out of their Home at 9 months in April or any of the summer months.
I had no problem reserving a 2 bdr. bwv in April, but I did call day-by-day at 11mos. exactly. But I wonder what the availablity is now even though it is still within the 8 mos ressie time frame?
I'd be curious to hear as well. Feel free to check and let us know.
Two weeks ago a friend checked on March availability for me at BWV. As of that time they had Two Bedroom villas availabile in all three categories for my week (standard, BW view and preferred). So no problems at BWV eight months out for March '08 (Easter is March 23rd.)
In the end if you are comfortable with the terms under which you bought BWV points, so be it. Some people don't assign any value to the extra years elsewhere and don't care about the higher dues.
That said, I think you're confusing people's paranoid desire to book day-by-day at 11 months with a true NEED to do so. Just because you read reports of a few people calling day-by-day for January (or April, or July) doesn't mean that people who wait until 10 months out are being told there is nothing available.
Personally, I enjoy sampling all of the different resorts and would have no problem sitting on the waitlist for a few months if necessary. The waitlist doesn't cause me the anxiety that it apparently does others. I've used my points at BWV three times so far--once Preferred View booked on very short notice and the other two times Standard View. The prognostications about things getting tougher and tougher to book have been floating about since I bought 4 years ago and, IMO, have yet to manifest in any measurable way.