I like the idea of relativity among positions, but I don't like that a terrible defensive catcher has a higher rating than a fantastic defensive 1B, for example (if I understand the range of ratings, which I'm not positive I do). And while the number would give one a general sense of a fielder's worth, I like the more specific ratings, such as range and arm, and I think they are even more important in determining value because they tell you strengths and weaknesses. It's more precise.