Comparing players across positions is precisely what WAR claims to do. From Fangraphs: "The goal of WAR is to provide a holistic metric of player value that allows for comparisons across team, league, year, and era and a framework for player evaluation. While there will likely be improvements to the process by which we calculate the inputs of WAR, the basic idea is something fans and analysts have desired for decades. WAR estimates a player’s total value and allows us to make comparisons among players with vastly different skill sets. Who is better, a slugging first baseman or a superlative defensive shortstop? WAR gives you a method for answering that question." https://library.fangraphs.com/misc/war/ Personally, I agree with Edwin Starr's evaluation of War: "What is it good for? Absolutely nothin'!"