There's a rule change worth mentioning that I am not sure everyone is aware of. It's actually not a change per se, just enforcement of a rule already on the books.
The "change" is that infielders will no longer be allowed to block a base with their foot or leg while fielding a throw on a tag play. This had become an art form in recent years.
The penalty is that the runner will be ruled safe at the advancing base. So if you try to steal second and the infielder is blocking the base, you are ruled safe at second. But if you are taking a lead off second, and the pitcher tries to pick you off, and the infielder is blocking the base as you dive back, you are ruled safe at third (the advancing base).
MLB is serious about promoting baserunning. Which puts an even greater premium on a catcher who can throw 'em out.