I think he is as good...if not better...than many experts predict. Reason being...as Disco has pointed out, he is a kid.
I remember Billy Slater spent a couple of seasons in the Origin wildness and was pushed onto the wing at times. I remember the hype around James Tedesco when he first came on the scene at the Tigers and had done far less than Tom T has at the same age.
You only have to look at the statistics to know that he is going to be ridiculously effective. When he was 19-20 years old he was already running for more metres with the ball in his arms, than any other player in the competition...I'll say that again...any other player in the ENTIRE NRL. The audacity of a kid to have so many touches, so many try assists, so many tries and so many metres at such a young age, is testament to his talent.
I do not understand how his defence comes into questions when he is asked to make 1-2 tackles a game...lots of fullbacks struggle to stop a two on one. I haven't seem him steam rolled yet. As for positional play, unless he is horribly late to grubber kicks and the opposition kickers are constantly finding the turf, I don't think you can say his positional play is poor.
He made a costly error two years ago against the Dogs, where he struggled to get down to a rolling ball, and that apparently equates to him having hands like feet?
He is playing in the most demanding position in the game (outside of maybe the dominant half in a team) game, and he is having a huge impact already.
Watching him play u/20's was like going to an under 6's game and seeing a 10 foot tall Polynesian who looked 5 years older than everyone else, running around the field. He was so physically superior to others in that NYC competition that he was scoring 4 tries a game and running for over 400m a match.
I remember he stepped up to FG that night against the Broncos at Gosford Stadium when he was still 18. He took a kick return and was faced with the Broncos kick chase. Most 18 year olds just pray they don't get smashed and look for the ground as quick as possible. Tom T (all of 18 years old) ran full tilt in between two defenders and popped a one handed, through the gate and around the corner pass to send Foran up field for a try (it was inside our own 20m zone too). I knew that night that he was destined for greatness.
The best players are not always the most consistent and they make errors...but when the game is on the line, things happen around them...Tom T is like this. That night in Canberra when Winterstein went through, Tom was off the hip and caught the ball one handed (such is the confidence) and raced over for the try...a true match winner and a Manly champion to be!