The amount of hits you give up is important in what a pitcher's ERA will be, but looking at hits allowed is a bad way to project anything. All i t is, is a product of your K/9. Generally, all pitchers will have the same BAA if you don't count AB's which lead to HR's. This is not true for extreme groundball pitchers, but it is for most pitchers. That's why I say it's useless; it doens't reflect a pitcher's skill, as much as our intuition tells us it does. Guys like RJ and Maddux have had great seasons of BAA, and horrible season of BAA.
As for watching guys play... yes it may show potential a pitcher has, but it also creates biases which seems to be the case with you and Blanton. It may not be pretty how he gets it done, but a K/BB that high in the PCL can't be ignored. IMO there's no rookie that will come close to him in ERA, other than Bush if you still consider him a rookie (technically he is).
The reason I emphasize K/BB is because those are the stats (K's and BB's) that pitchers directly control and for the most part aren't luck dependant, while ERA and BAA are luck dependant and aren't good for projecting future performance.
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