The recent trends in shift positioning has probably added some incremental weight to defense, while enhancing pitching stats . Hard hit ground balls or linedrives that used to be routine hits are now regular outs. Ask JBJr, when he does hit the ball. As noted above , contemporary defenses can make an average pitcher appear more effective than he actually deserves. How many games so far has Devers errors actually changed ? Did his misplay bother Brasier so much that the HR was allowed ?
A key defensive factor on team or individually is range. W quick defender will convert more of his chances , but may also incur a few more errors because he got to the ball, off balance or after a chase that lesser fielders couldn't make. Effective speed on foot (not a timed 40 yd dash) is a critical talent on offense and defense . Pitchers should want defenders behind them who can run. The Red Sox curent outfield is highly effective because Betts, Beni and Bradley can get to the ball more often than others .
The slick 'rocketball" and launch angle trend have made the HR a more significant part of the offense, where one hit is game changing in terms of score. . Josh Smith's one significant mistake last night was a single swing that won the entire game.
The one overweight factor for pitching is that every single action in the game is initiated by throwing the ball in the vicinity of home plate. Nothing happens without that catalyst. From there the effectiveness of the pitch is subject to many factors (location, movement, velocity, bat contact point, umpire calls , catcher framing/blocking) . Good to great pitching will almost always overcome hitters ability to reach base more than 25% of the time as seen in last night's game .
In regards to Moon's allocation of percentage ranking of positions, I would allow a little more to 1B (say 10%)and 3B , (say 12%) based on the perception that there are more hard hit balls down the lines which can more likely become doubles that hard grounders or line drives in the SS/2B vicinity. Also these two fielders must cover varying amounts of foul grounds and impediments like walls, dugouts and inebriated spectators than the other infielders chasing spinning foul balls.