Kershaw in the minors averaged 11 K/9 and 3.7 BB/9
Kerry Wood averaged 11 K/9 and around 6 BB/9 in the minors
Bartolo Colon averaged 9 K/9 and 3.3 BB/9 in the minors
Aaron Sanchez: 9.2 K/9 and 4.7 BB/9
You are cherry picking here. The only reasonable comp stat wise is Kerry Wood. But Wood, and even Kershaw, struck out more than 11 K/9 while Sanchez can barely maintain 8 K/9 above A+ while having a BB rate close to 5.
Sure Sanchez has the stuff but he really needs to work on his command if he wants to be more than just a wildcard at this point.