I replaced it with Hits/Game and also added in OBP
If you are going stat based alone, I would think runs scored/game and runs allowed/game would be included. ERA isn't all inclusive either (see Ar-kansas). Can't go by wins/losses and then go by win%/rank too, again, that is double dipping on selected stats. I'm sure there is a way to do a stat-only based comparison and come up with a decent ranking, but it hasn't been discovered yet. Looking at results and using human logic and human opinion is still the only way for now.