Basically, in a similar vein to the usual PvP proc nerfs, they have altered the effect of the trinkets to be half as potent, and last twice as long. But, fear not players who are using this for PvE, as Nakatoir clarifies, the change is only applicable in PvP environments. The tooltip hasn't yet been updated, as this requires a client side patch, but checking your character sheet while in a battleground or arena will reveal the change.
These changes will also be impacted in patch 5.3, when item level downscaling comes to PvP situations, as Nakatoir calculates, saying that "the value of the stat proc in 5.3 will be approximately 3454, with Superluminal lasting 40 seconds and Surge of Strength lasting 30 seconds". Players have still been asserting that this trinket is one of the best available, so it will be interesting to see if any further alterations are made. Nakatoir adds that the devs don't intend to prohibit PvE gear in PvP, so maybe there will be no further changes.