Dallas Braden improved against hitters in 2010. His .249/.294/.373 opposition slash line last season was a big improvement over his .268/.321/.397 line of the previous year. His wOBA came down over 20 points, from .314 to .292. It moved his number from good to great.
The reason for the improvement comes from more consistency in throwing his fastball. It's best seen against right-handed batters. In 2009, the movement of his fastball was spread out:
Righties compiled a .409 wOBA against Dallas's fastball that year. In 2010, his movement became much more consistent.
Braden was laser like, keeping the ball up and moving it in on righties. That led to a .283 wOBA by the opposition. His speed didn't change, but he located the pitch better.