I was never really impressed with new age data sets, ie, WAR and other numbers that come from slicing and dicing other data and now "normalized" against league averages and so on. Obviously a lot of baseball is played situationally with hitters and pitchers not in control of the trial events, and that tends to leave a poor sample size of comparable at bats with which to judge players against one another.
But when I got a look at this pic, I became even less enthralled with them, especially when there was some effort to apply the math to old time players and rate them against today's players:
If you look at Ernie Banks carefully, you will note his bottom hand is wrong on the bat; he has the bat in his palm, not his fingers. No coach today would teach a kid to hit like that; it is horrible form.
I kept looking out for stuff like that in old videos, and found it even in MLB Network highlight shows about the 1980's. You'll see good hitters stepping in the bucket and/or being outside the ball; fielders who don't get down enough to prevent batted balls from going through them; pitchers with inconsistent mechanics and being wide open as they complete the pitch. Also, in the absence of lots and lots of hard throwers, you can see hitters sitting on the fastball and being able to adjust much more commonly. It is actually pretty terrible to watch.
As a slight comparison, evaluating play based on football Moneyball type reporting isn't good at all: there have been a ton of very significant rule changes so trying to compare Joe Namath with Joe Montana with Joe Flacco with something like QB ratings makes no sense.
I think changing times have affected baseball at least as much. Between the added money that makes baseball players full timers; the addition of weight room and cross fit training to their regimens, the addition of video training, and the evidently much improved techniques that exist across the board and go to kids as early as ten and twelve years old, I think it is time to forget trying to use compiled data to judge who was good and who wasn't across time.
I just like to watch the games and not worry about WAR.