Yes, apparently it is getting harder. I just started a thread about my experience.
I called at 9:00am this morning on the first day I could for my reservation 11 months from now looking to book a treehouse villa from 12/27 to 1/3. The first day (12/27) was not available and I had to waitlist the entire 7 days, even though it was available for the other 6 nights.
So, if you're going at a busy time, don't expect that you'll definitely get what you want, even if you are the first to call 11 months in advance.