Homeruns were hardly a consideration when the first ballparks were being built. And merely having the same dimensions doesnt mean the parks will even remotely play the same. Can you imagine Colorado or Arizona having the same dimensions as everyone else? Philly & Cincy have "traditional" dimensions and they play like band boxes while Dodger stadium plays like an airport at night. Not only that, you are suggesting Fenway get rid of the green monster, Wrigley get rid of the ivy, and AT&T get rid if the Willie Mays wall.