Willie Mays displayed real versatility in all facets of the game, serving as the most valuable defensive piece in the MLB at center field each inning and immediately morphing into a batting juggernaut. In terms of his hitting game, he ranks top 10 all-time in WAR, Offensive WAR, WAR for position players, runs scored, and home runs (at 660). With a remarkable career batting average of .302 and an OPS+ of 156, Mays triumphed in many facets of slugging, but an even further level of his greatness came in his 12 Gold Glove awards for his mastery at center fielding. With 7,096 total putouts and a fielding percentage of 98.1%, he won rookie of the year, a batting title, National League MVP twice, and the 1954 World Series. Mays could simply do everything on the field every night, and few in baseball history could even come close to his domination in both offensive and defensive prowess. Willie Mays is the greatest ever because of his proficiency in every aspect of baseball, from center field to home plate.
Versatility does not immediately equate to greatness. Electing versatility as containing precedence over "greatness" in a single attribute excludes the players in history who were superior to Willie Mays in slugging, and those who were better than him at defensive play. His center fielding, aside, Mays is not ranked highly on many major statistical lists of fielding history, including putouts and assists. Since statistics are such a highly valued prerogative today, Mays' historical longevity on defense is severely lacking in these categories.
An individual player's adaptability is not determined by their proficiency in multiple subsets of one category, but by their skill in all categories. Versatility through all categories , as well as historical excellence in those categories, governs a player's bid for all-time greatness. Willie Mays displays more all-time distinction in offensive and defensive capability simultaneously than any other player in history, making him the best to ever do it.
[P1] Skill in multiple aspects of both offensive and defensive play is what makes a player truly versatile. [P2] Versatility in excellence over all facets of the game of baseball denotes greatness. [P3] Willie Mays is the only player in baseball history to make such profound and long-lasting statistical waves over both offensive and defensive play. [P4] Therefore, Willie Mays is the greatest baseball player ever.
Rejecting the premises
[Rejecting P1] Versatility is an arbitrary gauge of historical prominence, and placing priority in multiple playing classifications over excellence in one category is illogical. [Rejecting P2] Versatility does not intrinsically express greatness. [Rejecting P3] Willie Mays' record in some major defensive historical statistics is lacking. [Rejecting P4] The jump from "most versatile" to "greatest" is unfounded.