I don't think that this would be a good idea, the idea is that the sortorder title can be different from the actual title.
eg. for the Die Hard movies I have
Title.........................................Sort Order
Die Hard....................................Die Hard 1
Die Hard 2.................................Die Hard 2
Die Hard: With a Vengeance.....Die Hard 3
Live Free or Die Hard.................Die Hard 4
This groups the 4 movies together.
If I was to do as you say then if someone wanted to edit one of these then the sortorder would become the same as the title when saved destroying the purpose.
What I will do is add a button that on click copies the title to the sortorder.