I think the expat cabin crew are safe.
Igig: 2020 is possibly realistic if Saudi Arabia operated an EASA style operation but in fact the Saudi system is experience based and follows the FAA model. The Saudia management may have targets but currently don't have the power to force significant change on GACA. The flow of cadets in to Saudia will be relatively slow especially compared to companies in Europe like Easyjet or Ryanair, they will always want to keep average experience levels comparable with equivalent part 121 FAA Airlines. So of course you have vested interests in Saudi Arabia; GACA being one, Saudi management being another (and even differing factions within), the government a third, and they all have their power and priority which often conflicts.
No question though Saudiization is important to them and it will come at some point, especially if there is a period of stagnation in growth of the airline.