I seem to remember you stating that poor pitch-selection (bad batting eye) becomes apparent as a player advances through the minors. The symptoms being an increase in Ks and a decrease in BBs. The reasons are simple: better pitching at the higher levels. If memory serves me correctly, you used CPatterson to demonstrate this trend.
Looking at Vitters' numbers, I'm not seeing this. His BBs have increased at each level:
A/A+ = 20 BB in 618 PA
AA = 35 BB in 716 PA
AAA = 41 BB in 552 PA
Sure, the walk totals are not astounding, and the strikeouts have remained relatively consistent. But are there other explanations for these numbers? What am I missing here?