Cockpit already has the feature to display a column for “Next Task Due Date”, so even in the current state (pre task list view) you can sort by the next actual thing that is due.
With the current Success Plan view in horizon, there’s no way to see even when your next objective is due, let alone sort by it, so adding this as an available column would be very useful.
It’s probably rather unlikely you’d have an SP with no objectives, but consideration should be given to sorting by the new field if there is no objective (such as default to SP due date if no objective is present).