For narrative purposes, I can see why it wasn't included in the final cut of the episode. However, this scene should have been filmed at least to be included as a deleted scene on the DVDs. I felt like this had more conclusion to the Ponds and their story, giving more background to what happened to them and how they lived their lives. Also, it gives closure to Brian Williams regarding his son, which was very heartfelt and touching.
I will miss you, my beloved Ponds. ;__;