What is wrong with Chien-Ming Wang?

In a nutshell, there are two primary problems: control and groundballs.

Chien-Ming Wang's career BB/9 is 2.60; this season, his BB/9 is 4.34. Since May of 1 of last season, Chien-Ming Wang's BB/9 has been 3.98. Prior to that point in time, it had never been higher than 2.66.

On the bright side, Wang is striking out more guys this season than he ever has before. Since his first full season in 2006, Wang's strikeout rate has increased every season while keeping his BB rate relatively constant (until recently). Take a look at his seasonal K/9 rates:

'06: 3.14
'07: 4.70
'08: 5.12
'09: 6.75

While the increased whiffing is nice, Wang's K/BB has remained relatively stable over this period of time as well:

'06: 1.46
'07: 1.76
'08: 1.54
'09: 1.56

With '07 being the exception, Wang's walk rate has increased with his strikeout rate.

This is a problem for the following reasons:
1) More baserunners make big problems for pitch-to-contact pitchers. More guys on base plus more balls in play equals more hits, which equal more total bases, which equal more runs scored. Recall how little control pitchers have over balls in play resulting in hits or outs (see this article). The three year average BABIP on groundballs is .278 and Wang, a groundball pitcher, doesn't exactly have the rangiest middle infield behind him.
2) Wang has been giving up less groundballs lately. Despite a consistently high GB/FB rate throughout his career, Wang's groundball rate has dipped each season since his debut. Take a look at Wang's GB%'s by year since 2006:

'05: 63.9% (2.91 GB/FB)
'06 :62.8% (3.09 GB/FB)
'07: 58.4% (2.51 GB/FB)
'08: 55.0% (2.43 GB/FB)
'09: 45.2% (1.83 GB/FB)

Granted, Wang hasn't exactly been "healthy" this season (whether health be defined physically or mentally), but the decreasing trend in GBs is nothing new (albeit exaggerated this season). Wang has been consistently giving up more and more FBs, which means more and more opportunity for longballs (normalized HR/FB is 11%), which means more and more runs scored as the BB/9 increases.

What is to blame for Wang's troubles and trends? In my summation, it is the increasing reliance on the fastball, which has gotten worse each season. Here is Wang's 4 year FB%/wFB (wFB is the run value of a pitcher's fastball per 100 pitches) trend:

'06: 75.5%/18.8
'07: 76.4%/13.0
'08: 77.0%/8.6
'09: 85.9%/-12.6

Clearly, Wang's "injuries" (again, they may be mental or physical or both) have exaggerated the trend this season, but Wang's fastball (which has lost vertical movement and almost 2 MPH since 2006) has been eroding in effectiveness but increasing in usage -- a recipe for failure. At the expense of the increased fastball usage, the splitfinger change up and slider -- sharp breaking pitches that allow a pitcher to get on top of the ball -- have fallen out of favor.

Right now, Wang is "broken" in the sense that he's over-utilizing the wrong pitches. The fastball is down in velocity (perhaps attributable to physical injury) and his control is way off (perhaps attributable to mental struggles). Unless he starts mixing in his offspeed pitches more, I do not see Wang reclaiming his title as the king of groundballers.

What do you think? Do you agree/disagree? What do you think is to blame for Chien-Ming Wang's struggles?