Ok...So now that we have this information.. I would like us to know how much is this actually worth it.. Because I'm sure we all know that, in order to get Critical Rate, other statistics must be sacrificed. If determination and dexterity are sacrificed then we may be using more bloodletters but every single ability will deal a little less damage.
What we need to find is that harmonious balance of sacrificing other stats for critical, but making sure that the end result is higher damage, because afterall that is what we want; to make the job for the tank harder ;) :p
Edit: I suppose the higher crit on other abilities other than dots would offset this sacrifice and most likely will produce higher damage; just wanted to throw it out there for consideration.