I imagine the new ownership will value the 'If Rafa can work for these lot (Saudi state, etc) - that's good enough for me.' line tremendously. His appointment would go far in appeasing fans who are uneasy about being owned by the Saudi PIF.
If there is a manager who can galvanise the club under new (somewhat controversial owners), it's Rafa.
He is the right man is every aspect: he will continue building his vision for the club, from the ground up, thoroughly and at the right pace. He will not likely sign players who 'don't want to be here' and he will go about presenting the club is the same professional way that he had been doing before.
Rafa is absolutely the man for this job. Would he have issues working for the Saudis though? I'd have to assume that he would have his reservations...