A few quick stats points on Leake: his HR/9 is down to a career low 0.9, his BB/9 is down to a career low 1.9 and his K/9 is up to a career high 7.0. Obviously that's only half a season, but even if you've been skeptical about Leake and you're a complete slave to McCrackenized pitching analysis, surely you can recognize he's doing better at all of the things his critics insisted he needed to do better.
Now, I don't think it's terribly surprising to see a pitcher in his mid-20s improving on his first few seasons, especially when he didn't spend a day in the minors. However, if you had your doubts Leake had the capability to progress, all of the current indicators are that he indeed does. At the very least his performance has been encouraging.