Now I have no idea whether Tebow is a good quarterback or a bad quarterback. But these claims reminded me of a passage by Dallas Willard in Hearing God where he discusses the 19th century evangelist D. L. Moody.
In his day Moody was a constant source of wonder precisely because the effects of his ministry were so totally incommensurable, even incongruent, with his obvious personal qualities. He was a man of very ordinary appearance, unordained by any ecclesiastical group and quite uncultured and uneducated -- even uncouth and crude to many.
At the height of Moody's effectiveness, between 1874 and 1875, Dr. R. W. Dale, one of the leading nonconformist clergymen in England, observed his work in Birmingham for three or four days. He wished to discover the secret of Moody's power. After his observations were completed he told Moody that the work was most plainly the work of God, for he could see no relation between him personally and what he was accomplishing. A smaller person might well have been offended at this, but Moody only laughed and replied that he would be very sorry if things were otherwise.
Perhaps that's an explanation of why Tebow is so successful despite not being a good quarterback (assuming, of course, that it's true he's not a good quarterback). God sometimes reveals himself this way. And I suspect if someone told Tebow the same thing Dale told Moody he would respond the same way Moody did.