None of it? Last time I checked, fairness has a lot to do with the sport being fun.

Every arena being unique? Yeah, it does make it more exciting seeing people needing to hit farther for homeruns, or strategize where they hit. Like I said, it's something you need to actually experience in real life to understand it. Playing it WAS fun for me, until I had a heart attack and found out I couldn't play anymore because my heart is nearly one and a half times the size of a normal heart. It's fun to play when you're good at it, and its fun to watch when you're there.