It’s not exactly an experiment. The experiments happen in the minor leagues. I saw the ghost runner rule at a Somerset Patriots game years before the Major Leagues instituted it. They already know what differences the rule changes will make. What they can’t predict is how the fans will feel about it.
Also they have spring training to practice the new rules.
That’s all the time the big leaguers have to get used to it. The minor leagues get to try it out for a season or two to see how it works out.
The closest ballpark to me is the Somerset Patriots. Last season they became the Yankees AA team. Before that they were in the Atlantic League which was comprised of unaffiliated independent teams. A few years ago the independent league got an infusion of cash from MLB and in return they agreed to be the test bed for proposed new rules. Some of these rules were tried out for several seasons before MLB implemented them. They already have a very good idea what the impact on games will be.
It’s a sound strategy against Joey Gallo. For most batters it won’t be. If a pull hitter gets a hit against the shift in the past it’s a single. Pulling an outfielder means a double or more. You have to be damn sure he can’t adjust. Like Joey Gallo.
Indeed. Gallo seems to be the poster boy for the shift, being such an extreme pull hitter, and also apparently not being able to hit away from the shift. It seems like, any time there’s an article in the press (or a conversation here) about defensive shifts, Gallo’s name is brought up. (And, if the writer is intent on also bringing up history, they will also mention Ted Williams. 
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Except that a recent Fangraphs article greatly downplayed the effect of the shift on an extreme hitter like Gallo, who hits very few ground balls even to his pull side. Someone like Rafael Devers who has a lower swing plane and strikes out much less will likely get more of a boost.