Was pulling off aggro a couple of times from the tank again, even in Stone Vigil (doing my Trial of the Brave) earlier.

What I've noticed is that PLD seems to be more vulnerable to such issues. In fact all the aggro I've pulled or close to pulling are all PLD. The Japanese thread in OP seems to suggest so too. WAR doesn't seem to be affected or affected as much, but my raid's WAR told me that in 2.1 he could get away without Defiance on for dungeon stuffs but right now he don't think he can get away with it anymore.