Tracy

You're right. They did miss the boat on this opportunity. It might have made sense to put them together twice. Once before Arya went to Bravoos and once again after she completed training. Lyanna would have inspired Arya reminding her who she is and why she is fighting to begin with. I think Lyanna is a small slice of the North... Home... Though she may never have the homecoming she dreamed of, she has Lyanna to remind her what it means to be a small warrior ruling in the North.