I can only speak for custom weddings, but I'm not sure if that's what you are planning.
Disney has offered a 7:30 p.m. time slot for some time now. That is when my ceremony was, since we used the AAR for our reception.
The fortunate thing is that not a lot of people are interested in having their ceremony that late, so you actually have a better shot at it than earlier times. However, you have to factor in your reception location too. We got our WP time slot for Nov. 4th, but lost the lottery for the day overall due to AAR. We therefore had to move the wedding to Friday, but then Sunday.
The waiting is a pain and very nerve-wracking, but I maintain that you have a very good shot at it because most people don't want their ceremony (and their reception) to start that late. I think the 2:30 p.m. and 5:00 p.m. time slots are much more problematic in terms of getting your first choice.
Good luck!