Do they change for the better or worse?
As long as we can purchase a dining plan, we will be happy

I'm guessing when you book 11 months out it is an option?
We know why we are going to buy in (love of Disney and a we want to go every year or every other year). We heard about free APs from somewhere
and then to "keep" the APs found that there was a discount on renewals. We also went when they had free dining and now really want to have a dining plan when we go next.