They could possibly patch in variable meter of different sized zones if the meter isn't a still graphic (I've never noticed if the green zone size changes based on difficulty, but since there is no specific difficulty for fielding, I'll assume not). They could definitely at least implement meter speed differences based on player ratings.
Hell, I even went to the sliders to see if I could increase throwing errors, and while you can, you can't change the frequency for human errors, only generally...which I suspect only affects the computer (Something else 2K allowed you to do. You could change error frequency of both human and cpu, and it did affect the meter zones).