Facts are backed by reliable statistics, not opinions:
Valverde has had a BB/9 over 4 the last two years and over six this year. Fact.
Valverde has had a declining K rate since 2007. Fact.
Valverde's success has been BABIP (.247 last year) fueled. Fact.
In fact, a statistical decline was predicted by most projection systems, including ZIPS and Bill James.
But hey, 70 saves (the only stat worse than saves are RBIs) over the last two seasons.
You know who else had back-to-back seasons of sub 3.30 ERA and 70 saves? Francisco Cordero. Guess what? He sucks too, and now he's an afterthought.
The law of averages catches up to these pitchers who are a heart attack in the 9th inning eventually.
And by the way, both Valverde and Cordero (as well as Carlos Marmol, Kevin Gregg and the pitcher formerly known as Leo Nunez) are good examples of why closers are so overrated. Because of the sample, and the situations in which they pitch, otherwise ineffective relievers can be seen as "mid-tier" or even "near-elite" closers.
And those are actual facts, backed up statistically, not by opinion, unreliable samples, and bias.