I'm impressed with the work, bean, thanks. That is more stability than I expected in those figures. I still think that it won't work across eras, but maybe there is enough stability to use this metric for this era.
The other issue, which several people highlighted, is people who are hot for a period of time, and appear on the list, but are not aces, or people who are cold for a period of time, but are still aces. Dating myself, Anderson had a great freaking year and put himself on this list once upon a time, but Viola was the ace. Anderson was never an ace even if he won the ERA title that year. I think Carlos Silva probably made the list once upon a time as well.
That having been said, this is still useful. I just would take it with a grain of salt.