Where's JH? He'd love this tangent I think. The HR is still the easiest way to score. The shift is designed to try to get players to move away from that premium play for the offense. While it has become more prevalent my opinion is that it is still used against dead pull power hitters primarily.
By rotating the defense if hitters continue to pull it becomes more of an all or nothing proposition. If the ball stays in the yard the defense starts taking away the singles and doubles and knocks down the offensive productivity.
If you can make players give up the power stroke and go the other way the math really starts working in your favor. Limiting errors and walks makes scoring even one run require multiple base hits in any given inning. Since teams average 7 to 10 hits in a game they would have to put together as much as 1/3 to 1/2 of their offense in a single frame to plate 1 run. It is playing the odds.
Would teams make up the loss of HR's with higher base hit totals if they started going the other way against the shift? I m sure there are plenty of stats to make the point one way or the other. Since only 13 players hit 30 homeruns last year 2015 might be the year offensive players take what the defense gives in an effort to create more scoring opportunities.
As for Brian McCann - he gets $17MM per year because he is one of the relatively few players capable of hitting 25-30 HR's in a season anymore. Stanton and his deal says all there is to say about the value of the HR in MLB.
That's always been my take on it. It's used against power pull hitters. You can't take away their bread and butter, but you can be sure that if they miss they won't get a cheap hit because they got too far over it and pulled it through the hole or got too far under it and landed a duck snort into short right field.
While I think there might be generalities, the current "shift" approach, in my view, has clear exceptions. Where the exception was very visible was the post-season with the Giants who used the shift in every game/series with the Pirates, Nats, Cards and especially the Royals. Since the latter is talked about as being similar to the Giants, it seems clear the shift is viewed differently by different clubs.