Just remember, you were the one who said this:
Hamels vs. Shields: Hamels, but not by much. His ERA is lower, but he pitches in the NL.
Hamels' career ERA is 3.39, Shields' is 3.94. That's a difference of .55 runs per game. Yet you are saying Hamels but not by much. So in effect you are saying that ERA, in itself, is not totally reliable and needs to be adjusted for other factors. You may not realize it but you're contradicting yourself.