WAR is like many statistics

It tells a story that can be informative and also deceiving

The basic raw information, such as wins/losses, fielding average, RBI, even batting average) doesn't tell the whole story. So new statistics such as WAR were invented (for and by pencilheads) to try and remove variables like park dimensions/altitude, aberrational years (1930, high pitching mounds etc.). differences in time periods, strength of opponent to allow comparisons between players in a neutral environment and across the years. More sophisticated fielding and other measures were introduced to reward players for getting to balls and penalizing those with limited range.

One can justly argue that WAR is a comparison that is best done for players in the same time period. That a player from 1920 has the same WAR as a modern player doesn't mean that someone with the same skills as that 1920 player would have the same success in modern baseball. One could also argue that (like politics) using modern-day criteria to judge players from a previous generation emphasizes different qualities.

Apparently Bill James opposes using WAR as the ultimate decision point in close MVP races and thinks other data (late game/close game performance for one)should be factored into new statistics. He also believes WAR overrates older era players, since there was much more of a disparity in the statistics of top players from average players than would be found today. Sports data, even advanced metrics, can be beneficial, but also can tell the wrong story IMO.