Some minor qualifications. Sobers was picked originally for both Barbados and the West Indies as a slow left arm bowler, although his talent as a batsman was always recognized. He had a most unusual career trajectory. After his initial selection he was regarded as a batsman who bowled occasionally rather than as an all rounder. The Sobers of c.1960 was described as the world's greatest batsman, not the greatest all rounder.Not true for Sobers.
In his very second first class game he batted at number four. Above him were the openers and Weekes and Walcott. He was a child at 17.
He scored his first FC hundred in just his fifth game batting at number four.
Sobers was recognized as a true all rounder when he became a fast medium bowler around the time of the 1960-61 W.I. tour of Australia. A year or so later he added chinamen and googlies to his repertoire. Virtually all of his achievements as a true all rounder occurred from this period onwards.
Frank Worrell is a much better example. He was initially a slow left arm bowler before he became a great batsman..