The best thing that could happen to Formula 1 in 2019 would be a genuine shock in the season-opening Australian Grand Prix. Let's say Antonio Giovinazzi prevails for Sauber, that would be an upset right up there with the greatest in grand prix history.
Fans would be enthusiastic about how the formbook was turned on its head, delighted a middling team could suddenly leap to the front, thrilled that F1 had changed and the days until free practice started for the next race in Bahrain couldn't pass quickly enough.
So the unpredictability would be great for F1? If this happened in 2019, it would be.