He was a teen major champion, he won the junior AO...
Many players peak too early, he was a pretty good junior yes, but there have been many of those who end up poor as a pro, take Peliwo for instance, he has had an amazing run the last year making 4 junior major finals and winning 2, but is anyone talking him up as a future star of the game, no.
When his PTS come off of Brisbane and the AO his rank will fall, not go up, right now he just doesn't have what it takes to be a future star of this game.
tbf it's not just juniors he did well at - he won 2 Challengers when still a junior. Most people who win 2 or more Challengers as a junior tend to be guns, to varying degrees. That bodes well for Tomic, though there are always exceptions to the norm.
IMO he should start playing Challengers again. He'll be ranked around 80-90 post-AO if he doesn't improve his results, it'll be interesting to see whether he has the balls/heart required to get himself out of this downward spiral.