Bozo therein lies your fundamental flaw. Thurston, Fulton., Sterling etc were just talented kids when they came to grade, just like Kelly. Words such as they would never reach the heights of Gasnier, Churchill, Langlands, Dave Brown etc were probably being said just like you are saying of Kelly today. You're judging a player at the very beginning of his career, against the total careers of these champion players.
I contribute to Roar, sometimes write their articles, and found the same scope of thinking many years ago about Smith and Warner in cricket. A large number of contributors were derisive of these two before they entered the test arena. Smith was 'school boy cricket style', Warner 'would only be good as a one day player'. They refused to recognise that these kids were still developing. A close look could see both had that something special that was yet to fully bloom. In Smith it was a great eye and a fierce determination, in Warner it was also a great eye and despite being a big hitter, he could handle all sorts of bowling without faltering.
Kelly isnt the fastest centre, I'll agree. But speed isnt everything. Cliff Lyons didnt need it. Jamie Lyons was quick but not a speedster, Sterling wasnt fast at all. Fulton and Thurston were very fast but it was far more than speed that made them champion players. Kelly is quick, but not the quickest. What I see in his play is a clever football brain. If he develops that, he could turn into something special.
Judge them on their innate skills, Bozo, not by comparing them with the career best performances of players long passed. As I said, and I attended his matches in '66, Fulton was nothing special in his first year but he had that something special you could see that appeared every now and then. A year under his belt and he was becoming the champion, he became. I'm not suggesting Kelly will be as good as Fulton, but other than Lewis , who is? I think though Kelly has that something special buried in his youth that could develop him into a rep centre. He may fail, but he's got the skills to suggest he should be given the chance to succeed or fail.