I'm an old timer and most old timers don't like to hear this.
I don't think my dad's stats or any of the greats of the game would change if they played today.
Mays, Berra,. Musial, Williams, Joe D, Aaron etc.... would all be super stars today and adjust to the velocity.
BUT, theres no doubt in my mind they would strike out a lot more and have a far more difficult time bunting and hitting behind the runner with bat control.
The velocity and stuff these pitchers are throwing is just at a complete different level compared to when I played.