As mentioned before universal dimensions would still create hitters and pitchers ballparks. Let's say they took the huge outfield dimensions of the Rockies ballpark (where the ball still flies out of there regardless of how big the field is) and put that in San Francisco. There would never be a home run hit in San Francisco. The right field wall for the Giants is already nearly impossible to hit one out even though it's a very short distance from home plate.

The weather does have a big impact on the game. More home runs are generally hit on a warm day as opposed to a cold night. So colder weather regions are going to play different than hotter areas.

The terms hitter's park and pitcher's park wouldn't leave the game if there were universal dimensions, and we would lose the charm of individual parks. Huge NO vote here.