WAR's biggest flaw is positional adjustment for defense.

And particularly for first basemen. Keith Hernandez's career dWAR? 1.3. Don Mattingly? -6.2. Both are considered to be the two best defensive first basemen of all time and neither crack the top-1000 in dWAR. The all-time leader in dWAR, Roger Connor at 6.3, ties him for 502nd amongst all players.

I tend to look more at FanGraphs for defensive metrics because they include defensive runs saved, range, and zone ratings. But those only go back 20 years or so, which makes it tough to compare.*

*It is helpful to know that Derrick Jeter has the lowest Defensive Runs Saved of all time at -165.