I don't think ERA is the end of the world for discussions about pitchers either. However none of the various stats can be taken individually and to be honest some of the recent stat creations are just plain useless cause they are based on a false premise to begin with. Many of these things just become another means to make an excuse for not getting the job done. Others of the new generation of stats are great but I don't think a one of them is worth a damn on its own.
If a pitcher can't make enough good pitches he will end up with a poor performance. No matter how you cut it leaving pitches out over the plate will get you hurt....giving up walks will get you hurt. Pitching right into a particular hitters strengths will get you hurt.
If I cannot watch a pitcher pitch then I will often try to look at a number of stats to try to get a feel for what he is doing. However if I can see what a pitcher is actually doing, I won't depend on stats that much. I will look at the stats almost as a point of interest and to compare them to pitchers that I cannot see pitch.
As I posted recently that is what I don't like about complaints about flairs and the so called bitch hit. If a pitcher makes a poor pitch to a crummy hitter, the so called bitch hit or flair is a very likely result. Good hitters take mistake pitches and deposit them over the wall, poor hitters end up with flairs or the so called bitch hit off the same mistake pitch...does not chance the quality of the pitch...a s***** pitch is a s***** pitch. For the most part the genesis of hits, bitch hits, flairs, HR's, doubles whatever is a s***** pitch to begin with. Sometimes you can count on one finger or less the number of times hitters take a quality pitch and do something with it particularly during the course of a regular season game. All hitters are mistake pitch hitters which is why pitching is the single most important element of the game.