Board Thread:Questions and Answers/@comment-25322628-20170117173017/@comment-30791044-20170118065959

As much as I really wanted Mordo to be with Margaret, I think it was better he found someone else. The whole thing was just a reflection on how in life, we don't always get what we want, even after all the time we may have spent on it. But as we continue to do what we love doing, someone will come along, and she'll be everything you ever wanted.

I think the writers wanted to drive home that point.