I would not be prudent for the Pope to "start with a clean slate" and "turn back the clock" to the pre-1965 Mass. On the surface, it would be seen as "counter-revolutionary," but in reality, it would be revolutionary, in the sense it would cause unneeded chaos in the Catholic Church. Changes need to be done carefully.
Then gradually Tridentinizing the Novus Ordo's rubrics and adding deleted prayers to it over 20 years or so might be a step in the right direction.
The Anglo-Catholics already proved their Book of Common Prayer could be adapted to the rubrics of the Sarum Rite, so why can't the Novus Ordo be adapted to the rubrics of the Tridentine Mass, starting by restoring Psalm 42 at the foot of the altar.