Why It Works: Maggie Smith is the heart of Downton Abbey, but a period movie with another saucy and appealing elder member would keep the feeling of Downton while expanding into another family and community during the period.
Finally, people want to know what Rose is up to and this seems like the perfect opportunity for a solo spin-off.
The Plot: We know the romantic struggles and choices Lady Rose made during the series, but Lily James didn’t come back for the Downton Abbey movie, so we don’t have a good indication of what she’s been up to recently.
Plus, it would give the franchise the perfect opportunity to sign on someone awesome, like Diana Rigg.