Yes, he is still favorite at Fo and will be for as long as he enters the tournament but his %chances are dropping with every year.He is not getting better no matter how many adjustments he is trying to make.Rafa is still favored in 2 slams this year, and he always has the ability to win any slam. He lost to Cilic in 2018 and that worked out for him just fine.
Wish he would have kept number one, but he played a lot of tennis and is still healthy. Full expectation to pass fed in the next 12-16 months.
Thiem just played well on a surface that suits him, and Rafa did not play his best.
For as much crap people are giving to Zverev of Thiem, they are still getting better day by day and eventually will start breaking through.Thiem already has 2 Fo finals and this year will be a great chance for him to make his breakthrough.
Out of the Big 3 only Djokovic exudes an aura of invincibility, especially at Ao.Federer has been vulnerable for almost 2 years.
Nadal ,even though he just won Uso(the way he won that slam was not convincing at all, almost choked it all), has shown a lot of weaknesses.His server has become a very big liability.He can't count on it to end the sets or on very big points to save his life.If his Fh doesn't work he struggles.