I agree with Nick, Moffat did possibly leave options for S11 which I think is wonderful. I am really happy the way this series finale went. I had some doubts but I believe most of them were put aside. In everything, there will always be good points to the episodes and bad points, but I think the end really was quite impressive. I am strongly looking forward to the next series.
I do however think a lot of people assumed that Bill was only staying for one series. Now, however, I do not know. We will have to wait and see what comes next.