I do see some parallels in the cleverness of Thornton's ball hand-handling, but not sure I see anywhere near the same kind of finishing / scoring ability at this stage. Also, while Kyrie's not a John Wall / Russell Westbrook type athlete, he is 6'3 and did enter college with a lot more physical maturity -- far more than even his weight would suggest. In fact, what really surprised me about Kyrie on day 1 was how well he finished around the rim after absorbing contract.
While everyone focuses on Kyrie's ballhandling -- and that is clearly spectacular, he's a lot like Tyus Jones in that a lot of what makes him great is hard to clearly quantify or explain. For instance, while I wouldn't call Kyrie a spectacular leaper, I almost never see his shot get blocked at the rim b/c he has an innate sense of how to use his body to shield defenders, can shoot from a number of difficult arm angles, and is very creative with the spins he puts on the ball -- and Tyus had a lot of that as well. Because of that, I think it's dangerous to use a guys like Kyrie and Tyus as comparisons -- b/c a lot of what makes them great is very subtle and hard to replicate.